JP5189339B2 - Map display device, map display method, and map display program - Google Patents

Description

  The present invention relates to a technique for displaying map data on a display screen of a display unit.

  Conventionally, in screen scrolling and animation, when only a part of the screen changes, a part of the screen is newly drawn to reduce the burden of screen drawing. In other words, by drawing only the part that has changed on the screen and not drawing on the part that has not changed on the screen (that is, by not redrawing), it prevents unnecessary drawing. To be done. For example, Patent Document 1 describes a technique related to the present invention.

JP-A-9-16156

  However, when the drawing method that newly draws only a part of the screen as described above is performed, the drawn object straddles the boundary between the area that needs to be newly drawn and the area that does not need to be newly drawn However, there was a case where it was displayed with missing. This is considered to be because a drawn object straddling such a boundary was overwritten by newly drawing. In the technique described in Patent Document 1 described above, it has been difficult to appropriately suppress such a lack of display of a drawn object.

  Examples of the problems to be solved by the present invention include those described above. An object of this invention is to provide the map display apparatus, map display method, and map display program which can suppress appropriately that a drawing thing is missing and displayed at the time of a scroll.

According to a first aspect of the present invention, there is provided a map display device that displays a map on a display screen, a first storage unit that stores drawing data in an area including at least a display area on the display screen, and scrolling the map In the case of the above, the reusable area that can be displayed using the drawing data stored by the first storage means, the drawing data cannot be used, and a new drawing should be performed An area specifying means for specifying a new drawing area, a first drawing means for newly drawing a part of the new drawing area in the display area at the time of scrolling, and drawing by the first drawing means, A drawing sorting means for sorting a drawing that may not be displayed; a second storage for storing data of the drawing drawn by the drawing sorting means; Based on the data of the rendering object stored by second storage means, and a second drawing means redraws the drawing of the display area at the time of the scroll, the drawing object selection means, the A drawing that straddles the boundary between the reuse area and the new drawing area is selected as a drawing that may not be displayed as a whole .

According to a sixth aspect of the present invention, there is provided a map display method executed in a map display device for displaying a map on a display screen, wherein a first storage for storing drawing data in an area including at least a display area on the display screen. And a reusable area that can be displayed using the drawing data stored in the first storage step when the map is scrolled, and the drawing data can be used. First, a region specifying step for specifying a new drawing region to be newly drawn, a first drawing step for newly drawing a portion of the new drawing region in the display region at the time of scrolling, and the first drawing A drawing selection process for selecting a drawing that may not be entirely displayed by drawing in the process, and data of the drawing selected by the drawing selection process A second storage step for storing, and a second drawing step for redrawing the drawing in the display area at the time of scrolling based on the data of the drawing stored in the second storage step; The drawing object selection step is characterized in that a drawing object straddling a boundary between the reuse area and the new drawing area is selected as a drawing object that may not be displayed as a whole .

According to a seventh aspect of the present invention, there is provided a map display program executed in a map display device including a computer, wherein the first storage means for storing drawing data in an area including at least a display area on the display screen, When it is made, a reusable area that can be displayed using the drawing data stored by the first storage means, and a new area that cannot be used and the drawing data cannot be used newly Area specifying means for specifying a drawing area, first drawing means for newly drawing a part of the new drawing area in the display area at the time of scrolling, and drawing by the first drawing means may not be displayed entirely Drawing object selection means for selecting a drawn object having a characteristic, and second storage for storing data of the drawing object selected by the drawing object selection means Stage, on the basis of the data of the second of said drawing object stored by the storage means, the second drawing means redraws the drawing of the display area at the time of the scroll, makes the computer function as, the The drawn matter selection means selects a drawn matter straddling the boundary between the reuse area and the new drawn area as a drawn matter that may not be displayed as a whole .

  In one aspect of the present invention, a map display device that displays a map on a display screen includes first storage means for storing drawing data in an area including at least a display area on the display screen, and scrolling of the map. When it is made, a reusable area that can be displayed using the drawing data stored by the first storage means, and a new area that cannot be used and the drawing data cannot be used newly The whole area is displayed by area specifying means for specifying the drawing area, first drawing means for newly drawing a part of the new drawing area in the display area at the time of scrolling, and drawing by the first drawing means. A drawing object selecting means for selecting a drawing object that may not be performed, a second storage means for storing data of the drawing object selected by the drawing object selecting means, Based on the data of the stored said drawn product by the second storage means, and a second drawing means redraws the drawing of the display area at the time of the scroll.

  The above map display device is suitably applied to, for example, an in-vehicle navigation device, and displays a map on the display screen of the display unit. Specifically, the first storage means stores drawing data in an area including the display area on the display screen, and the area specifying means is stored in the first storage means when the map is scrolled. The reusable area that can be displayed using the drawn data and the new drawing area to be newly drawn are specified, and the first drawing means newly draws the portion of the new drawing area. Further, the drawn matter selecting means selects a drawn matter that may not be displayed entirely by the drawing by the first drawing means, and the second storage means stores data of the selected drawn matter, and the second The drawing means redraws the drawing object based on the drawing object data stored in the second storage means. As a result, it is possible to appropriately suppress the lack of display of a drawn object when scrolling. In addition, since only the stored drawing is redrawn, it is possible to prevent the drawing from being displayed with a minimum amount of redrawing.

  In one aspect of the map display device, the drawn matter sorting unit sorts a drawn matter straddling a boundary between the reuse area and the new drawn area as a drawn matter that may not be displayed as a whole. Thereby, it is possible to appropriately select a drawing to be redrawn.

  In another aspect of the map display device, the area specifying unit may be used as the reuse area when the map is scrolled among the areas in which the drawing data is stored by the first storage unit. A drawing data erasing unit that further specifies an open area including at least an unspecified area, and erases drawing data existing in the open area in the drawing data stored in the second storage unit. Is provided. As a result, the capacity of the memory used by the second storage unit can be reduced.

  In another aspect of the map display device, the first storage unit stores the drawing data in units of drawing areas divided into meshes, and the reuse area and the new drawing area are It is defined in units of drawing areas divided into meshes. This makes it possible to efficiently manage a reuse area, a new drawing area, and the like.

  Preferably, in the above map display device, the drawn matter sorting unit sorts a drawn matter straddling a boundary of the drawing area divided into the meshes as a drawn matter that may not be displayed entirely. As a result, it is possible to reliably prevent the drawn object from being displayed without being displayed regardless of the scroll direction or method.

  Preferably, the second storage means stores data of the drawn object in an area having an area equal to or larger than an area where the drawing data is stored by the first storage means. That is, the second storage means stores at least the data of the drawn object existing in the area where the drawing data is stored by the first storage means.

  In another aspect of the present invention, a map display method executed in a map display device that displays a map on a display screen is a first storage step of storing drawing data in an area including at least a display area on the display screen. And a reusable area that can be displayed using the drawing data stored in the first storage step when the map is scrolled, and the drawing data cannot be used. A region specifying step for specifying a new drawing region to be newly drawn, a first drawing step for newly drawing a portion of the new drawing region in the display region at the time of scrolling, and the first drawing step A drawing object selection step for selecting a drawing object that may not be displayed entirely by drawing, and data of the drawing object selected by the drawing object selection step is recorded. And a second drawing step of redrawing the drawing in the display area at the time of scrolling based on the data of the drawing stored in the second storage step. Prepare.

  In another aspect of the present invention, a map display program executed in a map display device including a computer includes: first storage means for storing drawing data in an area including at least a display area on a display screen; In the case of the above, the reusable area that can be displayed using the drawing data stored by the first storage means, the drawing data cannot be used, and a new drawing should be performed The whole area is not displayed by area specifying means for specifying a new drawing area, first drawing means for newly drawing a portion of the new drawing area in the display area at the time of scrolling, and drawing by the first drawing means. A drawing object selecting means for selecting a possible drawing object; a second object for storing data of the drawing object selected by the drawing object selecting means;憶 means, on the basis of the data of the second of said drawing object stored by the storage means, the second drawing means redraws the drawing of the display area at the time of the scroll, as to function the computer.

  Also by the map display method and the map display program described above, it is possible to appropriately suppress the lack of a drawn object and display when scrolling. Note that the map display program can be suitably handled in a state of being recorded on a recording medium.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The following description shows an example in which the present invention is applied to a vehicle navigation apparatus.

[Navigation device]
FIG. 1 shows the configuration of the navigation device 1. As shown in FIG. 1, the navigation device 1 includes a self-supporting positioning device 10, a GPS receiver 18, a system controller 20, a disk drive 31, a data storage unit 36, an interface 37, a communication device 38, a display unit 40, and an audio output unit 50. And an input device 60.

  The autonomous positioning device 10 includes an acceleration sensor 11, an angular velocity sensor 12, and a distance sensor 13. The acceleration sensor 11 is made of, for example, a piezoelectric element, detects vehicle acceleration, and outputs acceleration data. The angular velocity sensor 12 is composed of, for example, a vibrating gyroscope, detects the angular velocity of the vehicle when the direction of the vehicle is changed, and outputs angular velocity data and relative azimuth data. The distance sensor 13 measures a vehicle speed pulse composed of a pulse signal generated with the rotation of the vehicle wheel.

  The GPS receiver 18 receives radio waves 19 carrying downlink data including positioning data from a plurality of GPS satellites. The positioning data is used to detect the absolute position of the vehicle from latitude and longitude information.

  The system controller 20 includes an interface 21, a CPU (Central Processing Unit) 22, a ROM (Read Only Memory) 23, and a RAM (Random Access Memory) 24, and controls the entire navigation device 1.

  The interface 21 performs an interface operation with the acceleration sensor 11, the angular velocity sensor 12, the distance sensor 13, and the GPS receiver 18. From these, vehicle speed pulses, acceleration data, relative azimuth data, angular velocity data, GPS positioning data, absolute azimuth data, and the like are input to the system controller 20. The CPU 22 controls the entire system controller 20. The ROM 23 includes a nonvolatile memory (not shown) in which a control program for controlling the system controller 20 is stored. The RAM 24 stores various data such as route data preset by the user via the input device 60 so as to be readable, and provides a working area to the CPU 22.

  A system controller 20, a disk drive 31 such as a CD-ROM drive or a DVD-ROM drive, a data storage unit 36, a communication interface 37, a display unit 40, an audio output unit 50, and an input device 60 are connected via a bus line 30. Are connected to each other.

  The disk drive 31 reads and outputs content data such as music data and video data from a disk 33 such as a CD or DVD under the control of the system controller 20. The disk drive 31 may be either a CD-ROM drive or a DVD-ROM drive, or may be a CD and DVD compatible drive. The data storage unit 36 is configured by, for example, an HDD and stores various data used for navigation processing such as map data. The communication device 38 includes, for example, an FM tuner, a beacon receiver, a mobile phone, a dedicated communication card, and the like, and acquires information distributed from a VICS (Vehicle Information Communication System) center or the like.

  The display unit 40 displays various display data on a display device such as a display under the control of the system controller 20. Specifically, the system controller 20 reads map data from the data storage unit 36. The display unit 40 displays the map data read from the data storage unit 36 by the system controller 20 on the display screen. The display unit 40 includes a graphic controller 41 that controls the entire display unit 40 based on control data sent from the CPU 22 via the bus line 30 and image information that can be displayed immediately, such as a VRAM (Video RAM). A buffer memory 42 that temporarily stores, a display control unit 43 that controls display of a display 44 such as a liquid crystal display or a CRT (Cathode Ray Tube) based on image data output from the graphic controller 41, and a display 44 are provided. . The display 44 functions as an image display unit, and includes, for example, a liquid crystal display device having a diagonal size of about 5 to 10 inches and is mounted near the front panel in the vehicle.

  The audio output unit 50 performs D / A (Digital to Analog) conversion of audio digital data sent from the CD-ROM drive 31, DVD-ROM 32, RAM 24, or the like via the bus line 30 under the control of the system controller 20. A D / A converter 51 to perform, an amplifier (AMP) 52 that amplifies the audio analog signal output from the D / A converter 51, and a speaker 53 that converts the amplified audio analog signal into sound and outputs the sound into the vehicle. It is prepared for.

  The input device 60 includes keys, switches, buttons, a remote controller, a voice input device, and the like for inputting various commands and data. The input device 60 is disposed around the front panel and the display 44 of the main body of the in-vehicle electronic system mounted in the vehicle. When the display 44 is a touch panel system, the touch panel provided on the display screen of the display 44 also functions as the input device 60.

  Note that the CPU 22 and the like in FIG. 1 correspond to the map display device in the present invention. Specifically, the CPU 22 or the like corresponds to a first storage unit, a region specifying unit, a first drawing unit, a drawn object selecting unit, a second storing unit, a second drawing unit, and a drawn object data erasing unit. To do.

[Drawing method]
Hereinafter, the drawing method according to the present embodiment will be specifically described.

  In this embodiment, basically, when the map is scrolled, only the area that has changed in the display area is newly drawn, and the area that has not changed in the display area is not newly drawn. Adopt the method. Specifically, such a drawing method is realized by the following procedure. First, drawing data in an area including at least the display area on the display screen is stored, and a reusable area that can be displayed using such drawing data and the drawing data are used when scrolling. The new drawing area to be newly drawn is specified. The portion of the reuse area in the display area is displayed using the drawing data, and the new drawing area in the display area is newly drawn.

  Furthermore, in the present embodiment, as described above, by newly drawing a part of the new drawing area, a drawing that may not be displayed as a whole, in other words, a drawing that may be displayed with a part missing. And the data of the selected drawing is stored. Then, the drawing object is redrawn based on the drawing object data stored in this manner. As a result, it is possible to appropriately suppress the lack of display of a drawn object when scrolling.

  Next, a drawing method for newly drawing only a part of the display area will be specifically described with reference to FIG.

  FIG. 2A is a diagram for explaining a frame buffer used when the above drawing method is performed. A hatching area 71a in the drawing represents a drawing area stored in the frame buffer. The frame buffer corresponds to a buffer used for storing drawing data. The frame buffer is provided in the RAM 24 or the buffer memory 42, for example. Specifically, the drawing data is stored in the frame buffer in units of drawing areas divided into meshes, in other words, in units of units divided in a grid pattern. In this example, the frame buffer is defined by 12 drawing areas. In addition, a reuse area and a new drawing area, which will be described later, are also defined in units of such drawing areas divided into meshes. In the example shown in FIG. 2A, it is assumed that drawing data is not stored in the frame buffer, that is, the frame buffer is open. Hereinafter, an area in the frame buffer in which drawing data is not stored is referred to as an “open area”.

  FIG. 2B shows the state of the drawing area in the frame buffer before scrolling. In the drawing area in the frame buffer, as shown in FIG. 2B, there are an open area 71b indicated by hatching, a new drawing area 72b, and a display area 74b indicated by a bold line. In this case, the display area 74b is all newly drawn. Therefore, the entire display area 74b is configured by the new drawing area 72b. Here, since the new drawing area 72b is defined in units of drawing areas divided into meshes, the new drawing area 72b has a size slightly larger than the display area 74b.

  The drawing data in the display area 74b is stored in the frame buffer. As described above, since data is stored in the frame buffer in units of drawing areas divided into meshes, drawing data in the new drawing area 72b including the entire display area 74b is stored in the frame buffer. In this case, a drawing area in which drawing data is not stored in the frame buffer, that is, an area other than the new drawing area 72b in the drawing area in the frame buffer is an open area 71b.

  FIG. 2C shows the state of the drawing area in the frame buffer after scrolling. Specifically, FIG. 2C shows a diagram when scrolling in the direction indicated by the white arrow SC in FIG. 2B (that is, the lower right direction). As shown in FIG. 2C, the drawing area in the frame buffer includes an open area 71c indicated by hatching, a new drawing area 72c, a reuse area 73c, and a display area 74c indicated by a bold line. To do. In this case, the area that can be displayed using the drawing data in the frame buffer in the display area 74c is the reuse area 73c. Specifically, in an area where drawing data is stored in the frame buffer before scrolling (corresponding to the above-described new drawing area 72b), an area overlapping with the display area 74c after scrolling becomes a reuse area 73c. . Specifically, since the reuse area 73c is defined in units of drawing areas divided into meshes, it has a larger size than such overlapping areas. The portion of the reuse area 73c in the display area 74c is displayed using the drawing data stored in the frame buffer.

  On the other hand, the drawing data in the frame buffer cannot be used, and a new drawing area is a new drawing area 72c. Specifically, the part constituted by the display area 74c other than the reuse area 73c is constituted by the new drawing area 72c. Since the new drawing area 72c is defined in units of drawing areas divided into meshes, the new drawing area 72c has a size larger than that of the display area 74c except for the reuse area 73c. Here, the drawing data in the display area 74c is stored in the frame buffer. Specifically, since the data is stored in the frame buffer in units of drawing areas divided into meshes, drawing data in the reuse area 73c including the display area 74c and the new drawing area 72c are stored in the frame buffer. It will be. In this case, an area other than the reuse area 73c and the new drawing area 72c in the drawing area in the frame buffer becomes an open area 71c.

  Next, with reference to FIG. 3, a phenomenon in which a part of a drawing is missing and displayed by newly drawing will be specifically described.

  3A shows the state of the drawing area in the frame buffer before scrolling, and FIG. 3B shows the state of the drawing area in the frame buffer after scrolling. 3 (a) and 3 (b) correspond to the enlarged views of FIGS. 2 (b) and 2 (c), respectively, and examples of place names are displayed in an overlapping manner. Moreover, what attached | subjected the code | symbol same as FIG. 2 shall have the same meaning, and detailed description is abbreviate | omitted.

  When the map is scrolled in the direction indicated by the white arrow SC in FIG. 2B as described above, “Kawagoe City” and “Sayama” as indicated by the reference signs A1 and A2 in FIG. 3B, respectively. Some of the characters “city” may be displayed. It is considered that such a phenomenon can occur in a drawn object straddling the boundary between the reuse area 73c and the new drawing area 72c. Specifically, a drawing object straddling the boundary between the reuse area 73c and the new drawing area 72c is overwritten by newly drawing the new drawing area 72c, so that a portion in the new drawing area 72c in the drawing object is changed. Can be displayed missing. In the example shown in FIG. 3B, the characters “Kawagoe City” and “Sayama City” indicated by reference signs A1 and A2 cross the boundaries B1 and B2 between the reuse area 73c and the new drawing area 72c, respectively. Therefore, it can be said that a part of the image can be displayed.

  Next, a drawing method according to the present embodiment will be described. In the present embodiment, as described above, a drawn object that may be partially missing (in other words, a drawn object that may not be displayed as a whole) is selected, and data of the selected drawn object is stored. Specifically, a drawn object straddling the boundary between the new drawing area and the reuse area is selected and stored as a drawn object that may be partially missing. In this case, the selected drawing is registered in the redrawing data. Furthermore, in the present embodiment, not only a drawing object straddling the boundary between the new drawing area and the reuse area, but also a drawing object straddling the boundary of the drawing area divided into meshes may be partly missing. Select and memorize. That is, a drawing object that does not cross the boundary between the new drawing area and the reuse area but crosses the boundary in the mesh is selected and stored as a drawing object that may be displayed missing. Also in this case, the selected drawing is registered in the redrawing data. This is because, depending on the scrolling direction and method, there is a possibility that such a drawing may be displayed missing. In this embodiment, the drawing object is finally redrawn based on the drawing object data registered in the redrawing data. That is, redrawing is performed after drawing a new drawing area. As a result, the same drawing can be drawn again on the lacking drawing, and it is possible to appropriately prevent the drawing from being displayed when it is scrolled. In addition, since only the stored drawing is redrawn, it is possible to prevent the drawing from being displayed with a minimum amount of redrawing.

  Here, with reference to FIG. 4, the drawing method according to the present embodiment will be specifically described.

  FIG. 4A shows a view that is substantially the same as FIG. 3B (that is, an enlarged view of FIG. 2C). In addition, what attached | subjected the code | symbol same as FIG.3 (b) shall have the same meaning, and detailed description is abbreviate | omitted. As described above, when the map is scrolled in the direction indicated by the white arrow SC in FIG. 2B, the characters “Kawagoe City” and “Sayama City” indicated by reference signs A1 and A2 are reused. The border B1 and the border B2 between the region 73c and the new drawing region 72c are respectively straddled. Therefore, according to the drawing method according to the present embodiment, these characters are selected as a drawn material that may be partially missing, and the data of the drawn material is stored in the redrawing data. Then, the drawing object is finally redrawn based on the data of the drawing object registered in the redrawing data. As a result, the same character can be drawn again on the missing characters “Kawagoe City” and “Sayama City”. Therefore, it is possible to appropriately prevent the characters “Kawagoe City” and “Sayama City” from being displayed missing. That is, it becomes possible to display the whole of these characters appropriately.

  Furthermore, the characters “Sakado City” and “Koshisei-cho” (characters surrounded by a broken line) indicated by reference signs A3 and A4 in FIG. 4A are boundaries between the reuse area 73c and the new drawing area 72c. , But straddles the boundary B3 and the boundary B4 in the mesh, respectively. Therefore, according to the drawing method according to the present embodiment, these characters are also selected as a drawing that may be partially missing, and the data of the drawing is stored in the redrawing data. Drawings stored in this way will not be displayed in the current scroll, but may be missing depending on the future scrolling direction and method (for example, a complicated scrolling method that repeatedly moves forward and backward). It may be displayed. Therefore, by selecting and storing the drawn material in advance as described above, it is possible to appropriately suppress the lack of display regardless of the future scroll direction or method. Specifically, it is possible to appropriately prevent the characters “Sakado City” and “Ogosemachi” from being displayed without being displayed regardless of the scroll direction or method. In addition, it is also possible to specify the drawing object that may be displayed missing depending on the scroll direction and method in the future without separately selecting and storing in this way. By selecting and storing in advance as in the present embodiment, it is possible to reduce the burden of performing determination processing and the like, and to reliably suppress display of a missing part.

  FIG. 4B shows an example of redrawing data 100 in which data of a drawing object to be redrawn is recorded. Specifically, the drawing data stored when the map scrolls as shown in FIG. 4A is shown. The redrawing data 100 is stored in the RAM 24, for example. The redrawing data 100 is stored in a different procedure from the frame buffer for storing the drawing data. In the example shown in FIG. 4B, the redrawing data 100 stores data in which the name of the municipality and the position coordinates are associated with each other as indicated by a broken line 105, for example. Specifically, data in which coordinates are associated with names of “Kawagoe City”, “Sayama City”, “Sakado City”, and “Koshio Town” selected by the method described above is stored. Based on the drawing data in the redrawing data 100, the drawing is redrawn.

  Note that the redrawing data stores data of a drawn object in an area having a size equal to or larger than the drawing area in which the drawing data is stored in the frame buffer. That is, the data for redrawing is at least a drawing object existing in the drawing area in the frame buffer (in the example shown in FIG. 4A, an area composed of 12 areas divided by the mesh). Data is configured to be stored. In this case, the area used for storing the drawing object in the redrawing data is not limited to the same one as the drawing area in the frame buffer, but is set to a larger area than the drawing area in the frame buffer. May be. When the data of the drawn object in such a wide area is stored in the redrawing data, it is possible to reduce the process of selecting the drawn object and the process of storing the drawn object data.

  In addition, when an open area is specified at the time of scrolling, the data of the drawn object existing in the open area may be deleted from the redrawing data. For example, when scrolling as shown in FIG. 4A is performed, the data of “Koshisei-cho” existing in the open area 71c is deleted from the redrawing data 100 (see FIG. 4B). can do. As described above, by deleting the data of the drawn object from the redrawing data, the capacity of the memory used for the redrawing data can be reduced.

  Furthermore, although the example (refer FIG.4 (b)) which memorize | stores a character (name of a municipality) as a drawing thing in the redrawing data was shown above, it is not limited to this. In addition to such characters, a drawing such as a logo mark can be stored in the redrawing data as long as it crosses the boundary between the new drawing area and the reuse area or the boundary in the mesh.

[Drawing process]
Next, a drawing process according to the present embodiment will be described with reference to FIG. FIG. 5 is a flowchart illustrating the drawing process according to the present embodiment. This process is repeatedly executed by the CPU 22. Specifically, it is performed by the CPU 22 executing a program prepared in advance.

  First, in step S101, the CPU 22 determines whether or not the map has been scrolled. That is, it is determined whether or not a map scroll operation is performed. For example, the CPU 22 makes a determination based on a signal input to a touch panel (which functions as the input device 60) provided on the display screen of the display 44. If there is scrolling (step S101; Yes), the process proceeds to step S102. If there is no scrolling (step S101; No), the process exits the flow.

  In step S102, the CPU 22 performs a process of specifying a new drawing area. That is, the CPU 22 cannot use the drawing data stored in the frame buffer, and performs a process of specifying a new drawing area to be newly drawn. Specifically, a process for specifying a new drawing area to be newly drawn is performed from the scroll direction of the map, the area corresponding to the drawing data stored in the frame buffer, or the like. When the above process ends, the process proceeds to step S103.

  In steps S103 to S106, by repeatedly executing the process, a process for newly drawing a new drawing area and a process for selecting and registering a drawing object to be registered in the redrawing data are performed. First, in step S103, the CPU 22 performs a process for drawing each drawing data. That is, the CPU 22 performs a process for drawing the drawing data in the new drawing area. Specifically, the CPU 22 reads out map data corresponding to the new drawing area and performs drawing based on the map data. Then, the process proceeds to step S104. In step S104, the CPU 22 determines whether there is drawing data to be drawn in the new drawing area. Here, it is determined whether or not drawing in the new drawing area is completed. If there is drawing data (step S104; Yes), drawing in the new drawing area has not been completed, and the process proceeds to step S105. On the other hand, when drawing data does not exist (step S104; No), since drawing in the new drawing area is completed, the process proceeds to step S107.

  In step S <b> 105, the CPU 22 determines whether there is a drawn object that straddles the boundary in the mesh. Here, by newly drawing a part of the new drawing area, a drawing that may be displayed with a part missing (in other words, a drawing that may not be displayed entirely) is selected. Specifically, the CPU 22 takes into account the coordinates (reference points, etc.) of the drawn object, the size of the drawn object (such as the number of characters and fonts if the drawn object is a character), the scale of the map, etc. A process of selecting a drawing across the boundary is performed. When there is a drawing straddling the mesh (step S105; Yes), the process proceeds to step S106. In step S106, the CPU 22 performs a process of additionally registering the drawing object selected in the process of step S105 in the redrawing data. Then, the process returns to step S103. On the other hand, when there is no drawing straddling the mesh (step S105; No), the process returns to step S103. By repeatedly executing the processing of steps S103 to S106 in this way, all new drawing areas are drawn, and all drawing objects to be registered in the redrawing data are registered.

  On the other hand, the processing after step S107 is executed when the drawing in the new drawing area is completed (step S104; No). First, in step S107, the CPU 22 performs processing for specifying an open area. For example, in the drawing area in the frame buffer, the CPU 22 specifies an area that is not used as a reuse area or a new drawing area as an open area. Then, the process proceeds to step S108. In step S108, the CPU 22 performs a process of erasing the data of the drawing existing in the open area specified in step S107 from the redrawing data. Then, the process proceeds to step S109.

  In step S109 and step S110, the drawing is redrawn based on the data of the drawing in the redrawing data by repeatedly executing the process. Specifically, in step S109, the CPU 22 determines whether there is a drawing object to be redrawn. In this case, the CPU 22 determines whether or not the number of redrawn drawing objects (“0” when redrawing has not been performed) is less than the registered number of redrawing data. If there is a drawing object to be redrawn (step S109; Yes), in other words, if the number of redrawn drawing objects is less than the registered number of redrawing data, the process proceeds to step S110. In step S110, the CPU 22 performs a process of redrawing the drawing based on the data of the drawing in the redrawing data. Then, the process returns to step S109.

  On the other hand, when there is no drawing object to be redrawn (step S109; No), the process exits the flow. This case corresponds to a case where the number of redrawn objects is not less than the registered number of redrawing data. That is, the number of redrawn objects (“0” when redrawing is not performed) matches the registered number of redrawing data (“0” when there is no object to be redrawn) It corresponds to. For example, there is a case where there is no drawing object to be redrawn in the first place, or when redrawing of all drawing objects to be redrawn is completed. Therefore, in such a case, the process ends without performing redrawing.

  According to the drawing process according to the above-described embodiment, it is possible to appropriately suppress that a drawn object is missing and displayed during scrolling. That is, it becomes possible to appropriately display the entire drawn object. In addition, since only the stored drawing is redrawn, it is possible to prevent the drawing from being displayed with a minimum amount of redrawing.

  As described above, in this embodiment, the CPU in the navigation apparatus performs the first storage unit that stores the drawing data in the area including at least the display area on the display screen, and when the map is scrolled. An area for specifying a reusable area that can be displayed using the drawing data stored in the first storage means and a new drawing area that cannot be used for drawing data and is to be newly drawn By selecting means, first drawing means for newly drawing a part of the new drawing area in the display area at the time of scrolling, and drawing by the first drawing means, a drawn object that may not be entirely displayed is selected. A drawing object selecting means; a second storage means for storing data of the drawing object selected by the drawing object selecting means; and a drawing object stored by the second storage means. Based on over data comprises a second drawing means redraws the drawing of the display area at the time of the scroll, the. As a result, it is possible to appropriately suppress the lack of display of the drawn material when scrolling.

[Other embodiments]
The drawing process described above is assumed to be performed by the CPU 22 executing a program (map display program) prepared in advance, but instead, it may be performed by hardware processing in a circuit or the like. Further, the map display program may be stored in the ROM 23 in advance, or the program supplied from the outside by a recording medium such as a CD or DVD in which the map display program is stored and read by the disk drive 31 is stored in the ROM 23. It may be stored.

  In the above-described embodiment, the case where the map display device is applied to the navigation device has been described. However, the present invention is not limited to this and can be applied to a mobile phone, a PDA, and the like.

It is a block diagram which shows schematic structure of the navigation apparatus which concerns on an Example. It is a figure for demonstrating the drawing method which draws only a part in a display area newly. It is a figure for demonstrating the phenomenon in which a part of drawing is missing and displayed by drawing newly. It is a figure for demonstrating the drawing method which concerns on a present Example. It is a flowchart which shows the drawing process which concerns on a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Navigation apparatus 10 Self-supporting positioning apparatus 18 GPS receiver 20 System controller 22 CPU
24 RAM
36 Data storage unit 38 Communication device 40 Display unit 44 Display

Claims (8)

A map display device for displaying a map on a display screen,
First storage means for storing drawing data in an area including at least a display area on the display screen;
When the map is scrolled, a reusable area that can be displayed using the drawing data stored in the first storage means, the drawing data cannot be used, and a new An area specifying means for specifying a new drawing area to be drawn on,
First drawing means for newly drawing a portion of the new drawing area in the display area at the time of scrolling;
A drawing object selection means for selecting a drawing object that may not be entirely displayed by drawing by the first drawing means;
Second storage means for storing data of the drawn object selected by the drawn object selecting means;
Second drawing means for redrawing the drawing object in the display area at the time of scrolling based on the data of the drawing object stored by the second storage means ;
The map display device, wherein the drawing object selecting means selects a drawing object straddling a boundary between the reuse area and the new drawing area as a drawing object that may not be displayed as a whole . The area specifying means further includes an open area including at least an area that is not specified as the reuse area when the map is scrolled among the areas in which the drawing data is stored by the first storage means. Identify,
2. The map display according to claim 1, further comprising: a drawing data erasing unit for erasing the drawing data existing in the open area in the drawing data stored in the second storage unit. apparatus. The first storage means stores the drawing data in units of drawing areas divided into meshes,
It said recycle zone and the new drawing area, the map display device according to claim 1 or 2, characterized in that it is defined by a unit of divided drawing area to the mesh. The map display according to claim 3 , wherein the drawn matter sorting unit sorts a drawn matter straddling a boundary of the drawing area divided into the meshes as a drawn matter that may not be displayed as a whole. apparatus. 2. The second storage unit stores data of the drawing object in an area having an area equal to or larger than an area in which the drawing data is stored by the first storage unit. The map display apparatus as described in any one of thru | or 4 . A map display method executed in a map display device for displaying a map on a display screen,
A first storage step of storing drawing data in an area including at least a display area on the display screen;
When the map is scrolled, a reusable area that can be displayed using the drawing data stored in the first storage step, the drawing data cannot be used, and a new An area specifying step for specifying a new drawing area to be drawn on,
A first drawing step for newly drawing a portion of the new drawing area in the display area at the time of scrolling;
A drawing selection process for selecting a drawing that may not be entirely displayed by drawing in the first drawing process;
A second storage step of storing data of the drawn object selected by the drawn object selecting step;
A second drawing step of redrawing the drawing in the display area at the time of scrolling based on the data of the drawing stored in the second storage step ;
The map display method, wherein the drawing object selection step selects a drawing object straddling a boundary between the reuse area and the new drawing area as a drawing object that may not be displayed as a whole . A map display program executed in a map display device including a computer,
First storage means for storing drawing data in an area including at least a display area on the display screen;
When a map is scrolled, a reusable area that can be displayed using the drawing data stored by the first storage means, the drawing data cannot be used, and a new Area specifying means for specifying a new drawing area to be drawn;
First drawing means for newly drawing a portion of the new drawing area in the display area at the time of scrolling;
A drawn matter selecting means for selecting a drawn matter that may not be entirely displayed by drawing by the first drawing means;
Second storage means for storing data of the drawn object selected by the drawn object selecting means;
Based on the data of the drawn object stored by the second storage unit, the computer is caused to function as second drawing means for redrawing the drawn object in the display area at the time of scrolling ,
The map display program characterized in that the drawn matter selection means selects a drawn matter straddling a boundary between the reuse area and the new drawn area as a drawn matter that may not be displayed as a whole . A recording medium on which the map display program according to claim 7 is recorded.

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