JP2004133283A - Picture display device, picture display method, and picture display program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a picture display means for realizing smooth scroll display and preventing tearing, using picture memories efficiently. <P>SOLUTION: The picture display device is provided with: a display part (18) which displays pictures; two picture memories (14, 15) which have capacity corresponding to the number of pixels of the display screen of the display part; and a display control means (10) which writes picture data to be displayed in one side or both of the picture memories and also reads out the picture data from the picture memories and displays the data on the display part. At the time of displaying still pictures with scrolling, after the display control means determines the write-in position of the still pictures on the simplex logical memory space which is constituted by the combination of the two memories, the display control part performs the writing and the reading of the picture data to an area in the picture memory corresponding to the write-in position. Moreover, at the time of displaying moving pictures or different still pictures, after the part writes frame pictures constituting the moving pictures or different still pictures respectively in the two memories alternatively, the part reads out them. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image display device for displaying a moving image and a still image on a relatively small terminal device such as a mobile phone or a PDA (Personal Digital Assistant).
[0002]
[Background Art]
2. Description of the Related Art In a display device that displays a still image or a moving image, an image to be displayed (hereinafter, also referred to as a “source image”) is generally once written to an image memory and read out to display the image on a display screen. I do. If the display quality is not taken into account, it is possible in principle to display a still image or a moving image by using an image memory having a storage capacity corresponding to the number of pixels of the display screen, that is, an image memory for one screen. is there.
[0003]
However, when only one screen of image memory is provided, there is a problem that so-called scroll display requires time. Generally, the scroll display is a method of sequentially displaying different portions of one still image. However, when only one screen of image memory is provided, the scroll display is performed even though the source image is one still image. In addition, it is necessary to write the image data at the position after scrolling to the image memory and then read the image data each time, so that it takes time for the display process. Therefore, in order to realize a smooth scroll display, a method of using an image memory for one screen or more has been proposed. That is, after writing and displaying a part of a certain still image in the image memory, when scrolling, image data corresponding to the position after scrolling (after moving the display position) is written in the remaining part of the image memory and displayed (for example, , Patent Documents 1 and 2).
[0004]
On the other hand, when displaying a moving image, if there is only one screen of image memory, display disturbance (“Tearing”) occurs due to the asynchronous timing of writing and reading image data to the image memory. ") Is generated. That is, usually, the timing of writing image data to the image memory and the timing of reading are asynchronous, so if the image memory is only for one screen, the writing timing of image data will overtake the reading timing, or conversely, the reading timing will be The screen display is momentarily disturbed due to overtaking or the like (specifically, the display screen appears to be divided into upper and lower parts with a line on the screen where overtaking occurs as a boundary).
[0005]
In order to prevent this problem, a method has been proposed in which an image memory for two screens is used, and writing timing and reading timing are controlled so that overtaking does not occur to prevent tearing (for example, Patent Document 3). In addition, a method of simplifying control of write timing and read timing by using an image memory for two or more screens has been proposed (for example, Patent Document 4).
[0006]
[Patent Document 1]
JP-A-8-202524
[Patent Document 2]
JP-A-4-34496
[Patent Document 3]
JP-A-62-11889
[Patent Document 4]
JP-A-10-161842
[0007]
[Problems to be solved by the invention]
As described above, in order to realize smooth scroll display and tearing prevention, it is necessary to use an image memory for one screen or more. However, mobile phones and PDAs are not so large due to cost requirements. It is not possible to mount a large capacity image memory.
[0008]
The present invention has been made in view of the above points, and an image display apparatus and method capable of realizing smooth scroll display and prevention of tearing, and an image display capable of efficiently using a small amount of image memory. The task is to provide a program.
[0009]
[Means for Solving the Problems]
In one aspect of the present invention, an image display device includes: a display unit that displays an image; two image memories having a capacity corresponding to the number of pixels of a display screen of the display unit; Display control means for writing to one or both of the memories, reading the image data from the image memory, and displaying the image data on the display unit, wherein the display control means scrolls and displays the still image. After determining the write position of the still image on a single logical memory space configured by a combination of image memories, write and read the image data in an area on the image memory corresponding to the write position, When displaying a moving image or a different still image, a frame image constituting the moving image or the Wherein the reading the still picture to be after writing alternately.
[0010]
Further, from a similar viewpoint, an image display method executed in an image display device including a display unit for displaying an image and two image memories having a capacity corresponding to the number of pixels of a display screen of the display unit includes: When scrolling a still image, after determining a writing position of the still image on a single logical memory space formed by a combination of the two image memories, an area on the image memory corresponding to the writing position is determined. Writing and reading the image data, and when displaying a moving image or a different still image, reading and writing the frame image or the different still image constituting the moving image alternately in each of the two image memories. And
[0011]
The above-described image display device or image display method can be suitably applied to a portable terminal device such as a mobile phone or a PDA. Image data to be displayed is input by communication or another method. The display unit has a predetermined screen size, and two image memories having a capacity corresponding to the screen size are provided. By combining the two image memories, a virtual logical memory space for one screen or more of the display unit is configured.
[0012]
The image display includes a scroll display mode for scrolling one still image and a moving image display mode for displaying a moving image or a different still image. In the mode of scrolling a still image, image data for one screen or more can be written in the logical memory space, and scrolling is performed by changing the reading position within the range. A still image that is the basis of scroll display can be developed on one or more screens of virtual memory space, so the frequency of rewriting images to be displayed can be reduced, and smooth scroll display can be achieved by simply changing the read position. it can. On the other hand, in the moving image display mode, a moving image can be displayed without causing so-called tearing or the like by alternately writing frame images in the image memory for one screen, reading and reproducing the frame images in the order of writing. This is the same when displaying different still images in order. As described above, by efficiently using the image memory for two screens according to the display mode, it is possible to smoothly perform display in each mode with a limited memory capacity.
[0013]
In one aspect of the above image display device, the logical memory space arranges a part of one image memory in a horizontal direction with respect to the other image memory, and allocates a remaining part of the one image memory to the other image memory. The image memory can be arranged in the vertical direction. Accordingly, an additional memory space can be provided in both the vertical and horizontal directions with respect to the memory space for one screen, so that a smooth scroll display can be performed in both the vertical and horizontal directions.
[0014]
In another aspect of the image display device, when each of the image memories has a capacity capable of storing image data of h pixels in a vertical direction and w pixels in a horizontal direction, the logical memory space is The size can be 2w pixels and h pixels in the horizontal direction. As described above, by making the logical memory space an integral multiple of the image memory size for one screen, address conversion processing and the like can be simplified.
[0015]
In another aspect of the above image display device, the display control device receives a display command including the image data and a write position information of the image data in the logical memory space, and a display command in the logical memory space. Means for converting the write position information into position information in a physical memory space constituted by the image memory. As a result, the given position information in the logical memory space can be converted into position information in the physical memory space composed of two actual image memories, and an image can be displayed according to the display command.
[0016]
In another aspect of the above-described image display device, the display command includes designation information indicating whether to perform a scroll display of a still image or a moving image display, and the display control unit performs the static operation based on the designation information. Either scroll display of images or moving image display can be executed. Alternatively, the display control means may determine whether to perform scrolling of a still image or moving image display based on the writing position information in the latest display command and the writing position information in the previous display command. Can be determined.
[0017]
In another aspect of the above-described image display device, the display command includes scroll direction designation information for designating horizontal scroll and vertical scroll as a still image scroll display mode, and the display control unit determines that the horizontal scroll is designated. When the scrolling is performed, the two image memories are arranged side by side in the left and right direction to form the logical memory space, and when the up and down scroll is designated, the two image memories are arranged in the up and down direction and the logical memory space is formed. A space can be formed. Thereby, when the scroll direction is limited, a logical memory space is formed so as to secure the maximum memory space in the direction, and the frequency of writing image data at the time of scroll display is reduced, so that a smooth scroll display is performed. Becomes possible.
[0018]
In another aspect of the above image display device, the display command includes designation information of a portrait screen display or a landscape screen display, and the display control device, when the portrait screen display is designated, displays the logical memory space. In the case where the horizontally long screen display is designated, a horizontally long readout area can be defined in the logical memory space. As a result, even if the display screen is vertically long, it can be displayed horizontally, and vice versa. This change is to change the display area of the same still image to be vertically long or horizontally long, so that a specific part such as map data can be displayed in a desired manner, either vertically or horizontally. It becomes possible.
[0019]
In another aspect of the above-described image display device, the image display device has a fixed display area for displaying a specific image at a vertical position on the display screen, and an area corresponding to the fixed display area is located on the logical memory space. It can be located at the top or bottom. As a result, the above-described scroll display and moving image display can be performed using the remaining display area while performing a specific fixed display such as a telop at the upper and lower positions of the display screen.
[0020]
According to another aspect of the present invention, an image display program executed on a computer including a display unit that displays an image, and two image memories having a capacity corresponding to the number of pixels of a display screen of the display unit, When the computer scrolls and displays a still image, after determining a writing position of the still image on a single logical memory space composed of a combination of the two image memories, the image memory corresponding to the writing position is determined. The image data is written and read in the upper area, and when displaying a moving image or a different still image, the frame image constituting the moving image or the different still image is alternately written and read in each of the two image memories. It functions as display control means. By executing this image display program on a computer including a display unit for displaying an image and two image memories having a capacity corresponding to the number of pixels of the display screen of the display unit, the image display device described above is implemented. Can be realized.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0022]
[Mobile terminal device]
FIG. 1 shows a schematic configuration of a portable terminal device to which the image display method of the present invention is applied. The mobile terminal device 1 can be, for example, a mobile phone, a PDA, a handy personal computer, or the like. The mobile terminal device 1 is roughly divided into a host controller 2, a communication unit 3, an input unit 4, and a display processing unit 10. The host controller 2 is a controller that controls various elements mounted on the mobile terminal device 1, and includes a CPU, a RAM as a working memory, a ROM for storing various control data, a prepared control program, and the like. . By executing the control program, the host controller 2 comprehensively controls communication using the communication unit 3, detection of an instruction / input from the user to the input unit 4, image display by the display control unit 10, and the like.
[0023]
The communication unit 3 has an antenna 5 and the like as necessary, and functions when receiving image data or the like from the outside. For example, when the mobile terminal device 1 is a mobile phone and receives face image data from another mobile phone, the communication unit 3 performs communication processing. When the mobile terminal device 1 is a mobile phone, the communication unit is mounted in the mobile terminal device 1. However, when the mobile terminal device 1 is a PDA or a handy type personal computer, the communication unit is It may not be provided in the mobile terminal device 1 and may be configured as an external device.
[0024]
The input unit 4 is used for giving an instruction / input by a user's operation. When the mobile terminal device 1 is a mobile phone, the input unit 4 can be constituted by input buttons and the like. In the case of a personal computer of a handy type, it can be constituted by a touch pen type input device, a small keyboard or the like.
[0025]
The display processing unit 10 includes a panel 18 and an element for executing an image display process for displaying an image on the panel 18. As the panel 18, a liquid crystal panel or the like having a relatively small screen size is generally used, but various display devices other than the liquid crystal panel can be used. In the following description, it is assumed that the screen size of the panel 18 is horizontal 160 dots × vertical 240 dots.
[0026]
The display processing unit 10 further includes a host I / F 11, an operation control register 12, a memory write (write) control unit 13, a first frame memory 14, a second frame memory 15, a memory read (read) control unit 16, A driver 17 is provided. The host I / F 11 is an interface for transmitting and receiving necessary data to and from the host controller 2. The host I / F 11 mainly receives various commands for displaying an image on the panel 18 and display image data from the host controller 2. , To the operation control register 12 and the memory write control unit 13.
[0027]
The operation control register 12 receives a logical address given from the host controller 2 through the host I / F 11, generates actual physical addresses on the frame memories 14 and 15, and supplies the physical addresses to the memory write control unit 13 and the memory read control unit 16. I do. The memory write control unit 13 receives display image data from the host I / F 11, receives physical addresses (write addresses) on the frame memories 14 and 15 from the operation control register 12, and stores the display image data in the specified physical address. Write (write).
[0028]
Each of the frame memories 14 and 15 is a randomly accessible semiconductor memory having display pixels for one screen of the panel 18. The memory read control unit 16 reads (reads) display image data from the frame memory 14 and / or 15 according to a physical address (read address) given from the operation control register 12 and sends the read image data to the driver 17. The driver 17 performs a process of displaying the display image data on the panel 18. For example, when the panel 18 is a liquid crystal panel, the driver 18 is a semiconductor device having a segment driver for driving the data electrodes of the liquid crystal panel and a common driver for driving the scanning electrodes. Convert and supply.
[0029]
[First embodiment]
Next, a first embodiment using the above-described portable terminal device 1 will be described. In the first embodiment, scroll display of a still image and moving image display are performed using two frame memories 14 and 15.
[0030]
First, the memory configuration will be described. FIG. 2 schematically shows a configuration of a logical memory space and a physical memory space using two frame memories. The logical memory space is a memory space virtually configured using two frame memories, while the physical memory space is an actual memory space on the two frame memories.
[0031]
Now, as shown in FIG. 2, as a physical memory space, for a panel of w pixels in the horizontal (width) direction and h pixels (w <h) in the vertical (height) direction, w × h × 3 bytes (RGB 24 bits) 2) two frame memories are used. The two frame memories are referred to as “memory 0” and “memory 1” for convenience. In the example of FIG. 2, the memory 0 and the memory 1 each have 240 pixels × 160 pixels, and w = 160 and h = 240.
[0032]
Here, a logical memory space of W pixels in the horizontal direction and H pixels in the vertical direction is configured using two frame memories, that is, the memory 0 and the memory 1, as shown in FIG. Here, W = h and H = 2w. In this logical memory space, a display area (area (a)) of width w × h is defined corresponding to one screen size of the panel, and scrolling is performed using surrounding surplus parts (areas (b) and (c)). Display. An address in the logical memory space is called a logical address, and the vertical direction is indicated by a logical page address lpa, and the horizontal direction is indicated by a logical column address lca. Therefore, the logical page address lpa ranges from 0 to 319, and the logical column address lca ranges from 0 to 239.
[0033]
On the other hand, in the physical memory space, each of the memory 0 and the memory 1 corresponds to one screen size of the panel, and has two memory spaces of w × h. An address in the physical memory space is called a physical address. The physical address is indicated by a memory selection msel, a physical page address mpa0 and a physical column address mca0 of the memory 0, and a physical page address mpa1 and a physical column address mca1 of the memory 1.
[0034]
In the present embodiment, it is assumed that the memory 0 constituting the physical memory space corresponds to the frame memory 14 shown in FIG. According to the present invention, a smooth scroll display and prevention of tearing can be simultaneously realized by configuring a logical memory space using two frame memories. That is, when scrolling a still image, the logical memory space is assumed to be one virtual memory, and the image writing position is controlled on the virtual memory space. However, writing and reading of the actual still image are performed at a position in the physical memory space corresponding to a writing position in the logical memory space. Thus, the scroll display of the still image is performed using the memory space larger than one screen of the panel, so that the scroll display can be performed smoothly.
[0035]
On the other hand, when displaying a moving image, or when displaying a new still image different from the still image that has been displayed up to that time (both will be collectively referred to as “moving image display” below), An image for one screen of the panel is written to and read from two independent memories 0 and 1 respectively. Thereby, tearing or the like at the time of displaying a moving image can be prevented.
[0036]
FIG. 2 shows a correspondence between each area of the logical memory space and the physical memory space. As for the correspondence between the logical memory space and the physical memory space, the area (a) of the logical memory space corresponds to the area (A) on the memory 0 of the physical memory space, and the area (b) of the logical memory space corresponds to the area of the physical memory space. The area (c) in the logical memory space corresponds to the area (C) in the memory 1 in the physical memory space. As for the correspondence between the area (c) of the logical memory space and the area (C) of the physical memory space, the address from the left to the right of the area (c) of the logical memory space corresponds to the area (C) of the physical memory space. The correspondence is performed so as to correspond from the top to the bottom.
[0037]
The host controller 2 recognizes only the logical memory space. In other words, the host controller 2 recognizes the area (a) corresponding to one screen size of the panel and the surrounding areas (b) and (c) in the logical memory space, and uses the logical address. An image display command is supplied to the display processing unit 10. On the other hand, the operation control register 12 in the display processing unit 10 needs to convert a logical address given from the host controller 2 into a physical address on the frame memories 14 and 15.
[0038]
Specifically, at the time of scroll display of a still image, the host controller 2 gives a display command to the display processing unit 10 using all physical addresses in the areas (a) to (c) of the logical memory space. Therefore, the display processing unit 10 needs to convert logical addresses corresponding to all the areas (a) to (c) into physical addresses. FIG. 2 shows a conversion formula from a logical address to a physical address at the time of scroll display. As can be seen from the conversion formula, the logical address in the area (a) in the logical memory space directly corresponds to the physical address of the memory 0 in the physical memory space. Therefore, the converted physical address is memory selection msel = 0, physical page address mpa0 = logical page address lpa, and physical column address mca0 = logical column address lca.
[0039]
The logical address in the area (b) in the logical memory space corresponds to the physical address in the area (B) of the memory 1 in the physical memory space. Thus, the converted physical address is memory selection msel = 1, physical page address mpa1 = logical page address lpa, and physical column address mcal = lca-160.
[0040]
The logical address in the area (c) in the logical memory space corresponds to the physical address in the area (C) of the memory 1 in the physical memory space. Corresponds to movement in the direction. Therefore, the converted physical address is memory selection msel = 1, physical page address mpa1 = logical column address lca, and physical column address mca1 = logical page address lpa-160. Using the above conversion formula, the operation control register 12 converts a logical address given from the host controller 2 into a physical address on the frame memories 14 and 15 in the display control unit 10.
[0041]
On the other hand, at the time of displaying a moving image, temporally continuous frame images may be alternately written to and read from the memory 0 and the memory 1 in the physical memory space. In this case, the host controller 2 inputs the display addresses of all frame images to the display processing unit 10 as logical addresses corresponding to the area (a) in the logical memory space. Therefore, the conversion from the logical address to the physical address at the time of displaying the moving image is performed by switching the memory selection msel for each frame, and setting the physical page address mpa0 or mpa1 of the memory selected as the logical page address lpa, and similarly selecting the memory. In this case, the physical column address mca0 or mca1 which is set is equal to the logical column address lca.
[0042]
Next, an example of display control in the first embodiment will be described with reference to FIG. In the following example, it is assumed that the host controller 2 shown in FIG. 1 performs display control by transmitting a predetermined command to the display processing unit 10.
[0043]
First, as shown in state 1 in the upper left of FIG. 3, when displaying a single still image for the first time, the host controller 2 displays a command to write an image in the area (a) in the logical memory space. An instruction command is sent to the display processing unit 10. The display instruction command includes a logical address in the area (a) of the logical memory space, and the display processing unit 10 converts the received logical address into a physical address by the above-described address conversion method at the time of scrolling, and Write to memory 0 in memory space.
[0044]
An example of the display instruction command is shown below.
[0045]
(1) Page address set PSET (pset1, pset2): Specifies a logical page address.
[0046]
(2) Column address set CSET (cset1, cset2): Specifies a logical column address.
[0047]
(3) Memory write RAMWR: An instruction to start writing to the memory is sent, followed by display data.
[0048]
FIG. 4 shows a method of specifying a logical page address and a logical column address by the commands PSET and CSET. PSET specifies a vertical area between the arguments pset1 and pset2, and CSET specifies a horizontal area between the arguments cset1 and cset2. A write designation area in the logical memory space is designated by a combination of the two. Then, the start of writing is instructed by the command RAMWR, and subsequently the image data is sent to the display processing unit 10.
[0049]
The display control unit 10 converts the logical address given from the host controller 2 into a physical address according to the display instruction command, writes the physical address to each frame memory 14 and / or 15, and reads the frame memory 14 and / or 15 to read a still image. Will be displayed. In the state 1 shown in FIG. 3, since a still image is displayed first, the still image data for one screen of the panel is instructed to be written to the area (a) in the logical memory space. Data is written to the entire memory 0 (frame memory 14) and read from there.
[0050]
Next, when the still image displayed in the state 1 is scroll-displayed, a memory is used as shown in a state 2 in the upper right of FIG. That is, an additional image for scroll display is written into the areas (b) and (c) in the logical memory space by a scroll instruction command from the host controller 2, and then a scroll start position is specified. An example of the scroll instruction command is shown below.
[0051]
(1) Page address set PSET (pset1, pset2): Specifies a logical page address.
[0052]
(2) Column address set CSET (cset1, cset2): Specifies a logical column address.
[0053]
(3) Memory write RAMWR: An instruction to start writing to the memory is sent, followed by display data.
[0054]
(4) Scroll start set SCSTART: Specifies a scroll display start address.
[0055]
The write position of the additional image for scroll display is to write in a rectangular area in the logical memory space if scrolling only in the vertical or horizontal direction, but in the diagonal scrolling as shown in state 2 in FIG. In the case of, the additional image is written in the L-shaped area. In this case, either writing to two rectangular areas or writing once to the L-shaped area may be performed.
[0056]
In SCSTART, a page address / column address at the start of display after scrolling is specified. In the state 1 shown in FIG. 3, the display start address (page, column) = (0, 0). For example, when the display start address is specified as (10, 20) by SCSTART, 10 pixels are shifted downward, A scroll of 20 pixels is performed in the direction. If addresses are continuously processed on the assumption that the logical memory space is spherical when scrolling, scrolling in the upward and left directions becomes possible.
[0057]
When these commands are received from the host controller 2, the display processing unit 10 converts the logical address into a physical address according to the conversion formula shown in FIG. 2, and further displays an image from the physical address corresponding to the display start position. . Thus, scroll display is performed according to the amount of movement of the display start position from the original display start position (upper left of memory 0 in state 1). When continuing the scroll display, the host controller 2 scrolls by changing the display start position after writing the additional image in the areas (a) to (c) in the physical memory space.
[0058]
In the state 2 shown in FIG. 3, the host controller 2 issues a command to write an additional image to the areas (b) and (c) in the logical memory space. Additional images are written in B) and C) and read out from them to be displayed.
[0059]
Next, when moving image display or new still image display is performed from the state 1 shown in FIG. 3 (moving to the state 3), the host controller 2 stores new image data in the area (a) in the logical memory space. A display instruction command is generated to write (the first frame image of the moving image or a new still image) and supplied to the display processing unit 10. However, the new image data is actually converted from the logical address to the physical address in the display processing unit 10 so that the entire surface of the memory 1 in the physical memory space as shown in FIG. (A ') is written to prevent tearing due to overtaking of the write timing and the read timing as described above.
[0060]
Then, when performing still image scrolling (from state 3) (transition to state 4), the host controller 2 issues a scroll instruction command in the same manner as in the transition from state 1 to state 2 described above. . In this scroll instruction command, the host controller 2 instructs the areas (b) and (c) in the logical memory space to write the additional image for scrolling. Since it is written to 1, the scroll display is executed by allocating the areas (b) and (c) in the logical memory space to the areas (B ′) and (C ′) in the memory 0 in the physical memory space. Therefore, the relationship between the memory 0 and the memory 1 is switched as compared with the case of the state 2 in FIG.
[0061]
When displaying a new still image from any of the states 2 to 4, the display image may be written to the memory 0 in the physical memory space as shown in the state 1.
[0062]
In the present embodiment, as described above, when a scroll display of a still image is performed, an additional image for scrolling may be written to an empty area in the logical memory space and read. When displaying a new still image or displaying a moving image, the image data may be written to a physical memory opposite to the physical memory in which the still image has been written. As a result, during scroll display, smooth scroll display can be performed using the memory space of one screen or more of the panel 18, and at the time of moving image display, tearing due to overtaking can be prevented. Further, since these controls are performed by appropriately using the two frame memories, it is possible to realize even a terminal device such as a portable terminal having a limited image memory capacity.
[0063]
In this embodiment, as described above, the allocation of the memory 0 and the memory 1 on the two physical memory spaces to the logical memory space is switched between the scroll display and the moving image display (including the new still image display). However, to perform such switching, the display processing unit 10 needs to know whether the current state is a state in which scroll display is to be performed or a state in which moving image display is to be performed. One simple method for that is to provide the display processing unit 10 with a designation command indicating which state the host controller 2 is in. When the display processing unit 10 receives the command for specifying the scroll display, the display processing unit 10 may perform the address conversion according to the above-described logical address → physical address conversion formula at the time of scroll to allocate the physical memory, and specify the moving image display. When a command is received, address conversion may be performed according to the above-described logical address at the time of displaying a moving image → physical address conversion formula to allocate a physical memory. As such a dedicated command, for example, SCSTART in the above-described scroll display command can be used.
[0064]
Instead, the display processing unit 10 determines whether the scroll display or the moving image display should be performed based on the designation command from the host controller 2. It is also possible to determine based on the logical address in the command given from 2. This will be described in detail. As described above, the display instruction command from the host controller 2 includes the write designation area (defined by the logical page address and the logical column address as shown in FIG. 4) in the logical memory space of the image. ing. Therefore, based on the relationship between the write designation area designated by the previous display instruction command and the write designation area designated by the current display instruction command, scroll display or moving image display should be performed. It can be determined whether it is in the state. Specifically, (1) the current write designated area is included in the area (a) in the logical memory space, and (2) the address and size of the previous write designated area are the same as those of the current write designated area. When the two conditions of “equal to the address and the size” are satisfied, it is determined that the moving image should be displayed. This is because, as described above, when displaying a moving image or a new still image, the host controller 2 always designates the area (a) in the logical memory space and gives an image write instruction. That is, it is determined that a moving image should be displayed only when the entire area in which the image was previously written is completely rewritten, and that the scroll display is to be performed in other cases. This prevents a situation where a moving image should be displayed erroneously when, for example, only a part of the previously written image is rewritten. If the above two conditions are not satisfied, it may be determined that scroll display is to be performed.
[0065]
[Second embodiment]
Next, a second embodiment will be described. In the second embodiment, scroll display and moving image display are switched and executed basically using two frame memories in the same manner as in the first embodiment, but fixed display areas are provided above and below a display image. It differs from the first embodiment in that it is provided.
[0066]
FIG. 5 schematically shows a memory configuration according to the second embodiment. After defining a logical memory space by two frame memories 14 and 15 as shown in FIG. 5A, a fixed display area is defined above and below. In the example of FIG. 5, the height of the upper fixed display area is UFH pixel, and the height of the lower fixed display area is LFH pixel. Then, the lower fixed display area is moved below the upper fixed display area, and the upper and lower fixed display areas are integrated into one place and rearranged. Thereby, the address control between the fixed display area and the normal display area can be distinguished and simplified.
[0067]
FIG. 5B shows the physical memory space in this case. As in the case of the first embodiment, the areas (a), (b), and (c) of the logical memory space correspond to the areas (A), (B), and (C) of the physical memory space, respectively. Then, the area for (UFH + LFH) pixels from the top of the areas (A) and (B) in the physical memory space is allocated to the upper and lower fixed display areas.
[0068]
An image is displayed using the logical memory space and the physical memory space shown in FIGS. At the time of scroll display, scroll display is performed using an area excluding the upper and lower fixed display areas among the areas (a) to (c) in the logical memory space shown on the right side of FIG. FIG. 5B shows a conversion formula from a logical address to a physical address in that case. On the other hand, at the time of displaying a moving image or a new still image, as shown in FIG. 5B, the areas other than the upper and lower fixed display areas of the memory 0 and the memory 1 in the physical memory space are alternately used to form a frame. Write and display the image. At this time, the area above the area (C) in the physical memory space (pixels corresponding to the total height of the upper and lower fixed display areas) is not used at the time of displaying a moving image.
[0069]
FIG. 6 shows each state of scroll display and moving image (or new still image) display in the second embodiment. In state 5, the host controller 2 issues an instruction to write a still image to the area (a) in the logical memory space, and the display processing unit 10 writes the image to the area (A) of the memory 0 in the physical memory space. ,indicate. As a result, the image is displayed between the fixed display areas provided above and below on the actual display screen.
[0070]
When a scroll display instruction is issued in state 5 in FIG. 6, an additional image for scroll display is written in areas (b) and (c) in the logical memory space as in state 6. In that case, in the physical memory space, the additional image is written to the areas (B) and (C) of the memory 1 as shown.
[0071]
When an instruction to display a moving image or a new still image is issued in state 5 in FIG. 6, the instruction specifies the area (a) in the logical memory space. As shown, a frame image of a moving image or a new still image is written in the area (A ′) of the memory 1 in the physical memory space. When scroll display of a still image is instructed from the state 7, as shown in the state 8, the areas (b) and (c) in the logical memory space are changed to the area (B) on the memory 0 side in the physical memory space. ') And (C') are assigned and the image is written. Then, scroll display is performed by specifying the image display position as described above.
[0072]
In the state 7 in which the moving image display or the new still image display is performed, the upper right area of the memory 1 in the physical memory space is not used as described above. Further, in the state 8 in which the still image is scroll-displayed from the state 7, the upper right area of the memory 1 can be used to complement a part of the area (C ′) of the memory 0 (state 8). See figure).
[0073]
The upper and lower fixed display areas can be scrolled in a horizontal direction, for example, in addition to the fixed (for example, displaying the same still image) actually. In that case, the additional image is written and the display start position is changed within the fixed display area set above the areas (A) and (B) in the physical memory space shown in the state 5 in FIG. Just do it. As a result, for example, a telop display in which characters and the like flow horizontally can be performed.
[0074]
An example of the scroll instruction command in the present embodiment is shown below.
[0075]
(1) Area scroll set ASCSET: Initial setting of scroll display.
[0076]
(2) Page address set PSET (pset1, pset2): Specifies a logical page address.
[0077]
(3) Column address set CSET (cset1, cset2): Specifies a logical column address.
[0078]
(4) Memory write RAMWR: sends a memory write start instruction, and then sends display data.
[0079]
(5) Scroll start set SCSTART: Specifies a scroll display start address.
[0080]
ASCSET sets the scroll mode (whole screen scrolling, whether or not there is a fixed portion (portion that does not vertically scroll) in the upper portion or lower portion on the screen), and if there is a fixed portion, its height, etc. Command. In SCSTART, in addition to the display start address of the center scroll part, the display start address of the horizontal scroll of the upper and lower fixed part is also specified.
As described above, in the second embodiment, even when the fixed display areas are provided above and below the display screen, smooth scroll display and moving image display without tearing can be performed. In addition, address control can be simplified by concentrating the upper and lower fixed display areas on the logical memory space and the physical memory space. In the above example, the case where the fixed display area is provided on the upper side and the lower side is illustrated. However, the present invention can be similarly applied to the case where only one of the fixed display areas is provided.
[0081]
[Third embodiment]
In the first embodiment, two frame memories (memory 0 and memory 1 in the physical memory space) having a size of h pixels vertically and w pixels horizontally are combined to form a logical memory space of H = 2w pixels and W = h. The host controller issues an image display command by designating a logical address. On the other hand, in the third embodiment, when the scroll display command from the host controller includes the designation of the scroll direction (only horizontal scroll or only vertical scroll), the memory 0 and the memory 1 are arranged accordingly. To define the logical memory space.
[0082]
FIG. 7 schematically shows the method. Now, as shown in the lower part of FIG. 7, assume that a still image is written in only one of the memory 0 and the memory 1 in the physical memory space. Here, when the scroll display command from the host controller 2 includes the designation of the left and right scroll, as shown in the center of the upper part of FIG. Is composed. This enables horizontal scroll display based on image data for two screens in the horizontal direction. When the scroll display command from the host controller 2 includes designation of up / down scrolling, the memory 0 and the memory 1 are vertically connected as shown in the upper right of FIG. Constitute. As a result, vertical scroll display can be performed based on image data for two screens in the vertical direction.
[0083]
On the other hand, when the scroll designation is not included in the scroll display command from the host controller 2, or when the up / down / left / right scroll designation is included, as shown in the upper left of FIG. A logical memory space similar to that of the embodiment is configured. As described above, when the scroll direction is determined by the command from the host controller 2, the memory 0 and the memory 1 are arranged so that the physical memory space is maximized in that direction, so that the image is rewritten during the scroll display. The number of times can be reduced (for example, in the case of vertical scrolling, it is not necessary to write an image when scrolling down one screen and then scrolling up one screen again).
[0084]
In the third embodiment, in order to prevent the display image from being disturbed, the condition is that the image is written in only one of the memories 0 and 1 in the physical memory space at the start of the processing as described above. (That is, it is impossible when an image is written across both memories). Further, the condition is that the fixed display area is not defined as in the second embodiment.
[0085]
[Fourth embodiment]
The fourth embodiment provides a method of displaying a vertically long display image in a horizontally long state at the time of left and right scroll, and its outline is shown in FIG. Now, a state in which scrolling in the left-right direction is performed (at the time of scrolling up and down and right and left as shown in FIG. 8A or at the time of right and left scrolling as shown in FIG. And For example, as shown in FIG. 8A, when a part of the logical memory space is scroll-displayed on the portrait screen, and receives a landscape screen display instruction from the host controller 2, the display processing unit 10 As shown in FIG. 8B, the read area is defined to be horizontally long on the same logical memory space. As a result, an image that has been displayed on a vertically long screen can be displayed on a horizontally long screen. 8C, the display processing unit 10 receives the instruction to display the horizontally long screen from the host controller 2 and specifies the read area to be horizontally long as shown in FIG. Can be displayed on a landscape screen.
[0086]
Such a process is suitable, for example, when viewing map data and the like on a mobile terminal device 1 having an originally vertically long display screen, such as a mobile phone. That is, since map data of a certain area is normally displayed on a vertically long screen while being written in the entire physical memory space, image data obtained by vertically cutting a part of the map data is displayed. Here, for example, when the user operates the input unit 4 of the portable terminal device 1 to input an instruction to display a landscape screen, the display processing unit 10 defines the lead area as landscape as described above and stores the image in the memory. 0 and memory 1 and display. As a result, the map data normally displayed long in the north-south direction can be displayed long in the east-west direction by the landscape display.
[0087]
In this case, in practice, the display processing unit 10 needs to control the reading direction of the image data from the read area defined in the landscape. This is because the scanning direction of the panel 18 of the mobile terminal device 1 is fixed. When a normal portrait screen is displayed, the panel 18 is scanned, for example, in the direction of an arrow 40 shown in FIG. 8A. Therefore, when a landscape screen is displayed, the image data is scanned from bottom to top as shown by an arrow 41 in FIG. Must be read out and displayed on the panel 18 in that order. This control can be performed by the display processing unit 10 changing the reading position and order in the physical memory space based on whether the display is the portrait display or the landscape display.
[0088]
According to the present embodiment, a horizontally long screen display can be performed by a mobile terminal device which originally has a vertically long screen. Conversely, it is also possible to display a portrait screen on a portable terminal device that normally has a landscape screen.
[Brief description of the drawings]
FIG. 1 shows a schematic configuration of a portable terminal device to which an image display method according to the present invention is applied.
FIG. 2 shows a relationship between a logical memory space and a physical memory space in the first embodiment.
FIG. 3 shows a method of using a memory space according to the first embodiment.
FIG. 4 schematically illustrates a method of specifying a writing area in an image display command.
FIG. 5 shows a relationship between a logical memory space and a physical memory space according to the second embodiment.
FIG. 6 shows a method of using a memory space in a second embodiment.
FIG. 7 shows a method of using a memory space in a third embodiment.
FIG. 8 shows a method of using a memory space in a fourth embodiment.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 mobile terminal device, 2 host controller, 3 communication unit, 4 input unit, 10 display processing unit, 11 host I / F, 12 operation control register, 13 memory write control unit, 14, 15 frame memory, 16 memory read control unit , 17 drivers, 18 panels

Claims (11)

A display unit for displaying an image,
Two image memories each having a capacity corresponding to the number of pixels of a display screen of the display unit;
Display control means for writing image data to be displayed to one or both of the image memories, reading the image data from the image memory, and displaying the image data on the display unit,
When scrolling a still image, the display control means determines a writing position of the still image on a single logical memory space composed of a combination of the two image memories, and then determines the writing position of the still image. The image data is written and read to and from the area on the image memory, and when displaying a moving image or a different still image, a frame image constituting the moving image or the different still image is alternately written to each of the two image memories. An image display device characterized by reading out the data afterwards. The logical memory space arranges a part of one image memory in a horizontal direction with respect to the other image memory, and arranges a remaining part of the one image memory in a vertical direction with respect to the other image memory. The image display device according to claim 1, wherein the image display device is configured by: When each of the image memories has a capacity capable of storing image data of h pixels in the vertical direction and w pixels in the horizontal direction, the logical memory space has a size of 2w pixels in the vertical direction and h pixels in the horizontal direction. The image display device according to claim 1, wherein: The display control device,
Means for receiving a display command including the image data and write position information of the image data on the logical memory space,
4. A means for converting the write position information on the logical memory space into position information on a physical memory space configured by the image memory. The image display device as described in the above. The display command includes designation information indicating whether to perform scroll display of a still image or moving image display, and the display control unit executes either the scroll display of the still image or the moving image display based on the designation information. The image display device according to claim 4, wherein: The display control means determines whether to perform scroll display or moving image display of a still image based on the writing position information in the latest display command and the writing position information in the previous display command. The image display device according to claim 4. The display command includes scroll direction designation information for designating horizontal scroll and vertical scroll as a scroll display mode of a still image,
The display control means forms the logical memory space by arranging the two image memories side by side when the left / right scroll is specified, and the two image memories when the up / down scroll is specified. 5. The image display device according to claim 4, wherein the logical memory spaces are formed by arranging the logical memory spaces in a vertical direction. The display command includes designation information of a portrait screen display or a landscape screen display, and the display control device defines a portrait read area on the logical memory space when the portrait screen display is specified, and 5. The image display device according to claim 4, wherein when display is specified, a horizontally long read area is defined on the logical memory space. It has a fixed display area for displaying a specific image at an upper and lower position of the display screen, and an area corresponding to the fixed display area is arranged at an upper end or a lower end in the logical memory space. The image display device according to claim 1. An image display method performed in an image display device including: a display unit that displays an image; and two image memories each having a capacity corresponding to the number of pixels of a display screen of the display unit,
When scrolling a still image, after determining a writing position of the still image on a single logical memory space formed by a combination of the two image memories, an area on the image memory corresponding to the writing position is determined. Writing and reading the image data, and when displaying a moving image or a different still image, reading and writing the frame image or the different still image constituting the moving image alternately in each of the two image memories. Image display method. An image display program executed on a computer including a display unit that displays an image, and two image memories each having a capacity corresponding to the number of pixels of a display screen of the display unit.
When scrolling a still image, after determining a writing position of the still image on a single logical memory space formed by a combination of the two image memories, an area on the image memory corresponding to the writing position is determined. Display control means for performing writing and reading of the image data and displaying a moving image or a different still image when the frame image or the different still image constituting the moving image is alternately written and read in each of the two image memories. An image display program characterized by functioning as:

Images