JP3703814B2 - How to create a circle - Google Patents

Description

【００３０】
と、線分の長さｌとによって表すことができる。この内、線分の方向単位ベクトルはｘ軸方向の単位ベクトルａとｙ軸方向の単位ベクトルｂとを使って、
【００３１】
【数１】

【００３２】
で表すことができるので、線分の図形要素を示すデータは、ｘ0 、ｙ0 、ａ、ｂ及びｌによって表され、図１１（Ｂ）に示したような形式で保持される。データの先頭は図形要素の種類を表すタイプ番号となっており、ここには２次元の線分の場合、たとえば「２」が割り当てられている。図形を描いたときに一意に決まる図形要素の識別子（ＩＤ）は、このタイプ番号のあるデータの先頭アドレスを表すようにしている。なお、線分の長さは、ｌ＞０であるが、ｌ＝０の場合は無限線を表し、ｌ・１６．０×１０³¹（実数値の最大値の平方根）は半無限線を表す。
【００３３】
図１２（Ａ）は２次元の円を表現した図であり、図１２（Ｂ）は円の図形要素のデータ形式を示した図である。これらの図に示したように、２次元の円は、その中心位置の座標（ｘ，ｙ）と半径ｒとによって表すことができる。円の図形要素を示すデータとしては、円弧の場合とデータ形式を同一にするため、この他に、始角θ1 及び終点までの相対角θ2 （単位はラジアン）が加わり、図１２（Ｂ）に示したような形式で保持される。なお、円の場合は、始角θ1 は「０」に、終点までの相対角θ2 は「２π」にそれぞれ固定された値で保存される。また、２次元の円にはタイプ番号として、たとえば「５」が割り当てられている。
【００３４】
図１３（Ａ）は２次元の円弧を表現した図であり、図１３（Ｂ）は円弧の図形要素のデータ形式を示した図である。これらの図に示したように、２次元の円弧は、その中心位置の座標（ｘ，ｙ）と、半径ｒと、始角θ1 と、終点までの相対角θ2 とによって表すことができる。始角θ1 は、
【００３５】
【数２】
−２π＜θ1 ≦２π ・・・（２）
の値をとり、終点までの相対角θ2 は、
【００３６】
【数３】
−２π≦θ2 ≦２π（θ2 ≠０）・・・（３）
の値をとる。円弧の回転方向は、終点までの相対角が、θ2 ＞０のとき左廻り、θ2 ＜０のときは右廻りとなる。２次元の円弧にはタイプ番号として、たとえば「６」が割り当てられている。
【００３７】
図１４はナビゲーション表示装置の原理を示した構成図である。この図によれば、ナビゲーション表示装置は、直線、円及び円弧の図形要素の情報を格納している図形要素情報記憶手段１を有しており、表示手段２がその図形要素情報記憶手段１から読み出した情報に基づく図形を表示する。その表示手段２は図形要素情報記憶手段１に格納されている図形要素情報を表示情報に変換する表示制御手段２ａと、その表示情報を記憶する表示情報記憶手段２ｂと、この表示情報記憶手段２ｂに記憶された表示情報を表示する表示部２ｃとより構成されている。ナビゲーション表示装置はさらに、図形要素の検索範囲、カーソルの現在位置及びヒット位置を認識するカーソル情報認識手段３と、表示手段２において表示中の図形要素の中からカーソルの現在位置に近い図形要素を検索する図形要素検索手段４と、この図形要素検索手段４によって検索された図形要素からその図形要素の特定点を生成する特定点生成手段５と、カーソル情報認識手段３からのカーソルのヒット位置及び現在位置から創成しようとする図形要素を一時的に生成するラバーバンド生成手段６と、特定点生成手段５にて生成された特定点及びラバーバンド生成手段６にて生成されたラバーバンドの表示位置を算出する表示位置算出手段７とを有している。また、図示はしないが、表示位置算出手段７は、特定点生成手段５にて生成された図形要素の持つすべての特定点の内、カーソルに最も近い特定点を算出して、表示手段２に強調表示を指示する手段を有している。
【００３８】
図示のナビゲーション表示装置によれば、図形要素情報記憶手段１にはＣＡＤシステムにおいて作成された図形要素の情報などが格納されている。表示手段２はこの図形要素情報に基づいて図形要素を表示する。表示手段２では、表示制御手段２ａが図形要素情報記憶手段１に格納されている図形要素情報を表示情報に変換し、表示情報記憶手段２ｂにおいてその表示情報を記憶し、表示部２ｃにて表示情報記憶手段２ｂに記憶されている表示情報を表示する。カーソル情報認識手段３では、カーソルを中心とした図形要素の検索範囲、カーソルの現在位置及びマウスのボタンをクリックすることによって得られたヒット位置を認識する。図形要素検索手段４は表示手段２において表示中の図形要素の中からカーソルの現在位置に近い図形要素、すなわち、検索範囲内にある図形要素を検索する。特定点生成手段５で、図形要素検索手段４によって検索された図形要素からその図形要素の特定点を生成し、ラバーバンド生成手段６では、カーソル情報認識手段３からのカーソルのヒット位置及び現在位置を基にして創成しようとする図形要素を一時的に生成する。これら特定点生成手段５にて生成された特定点及びラバーバンド生成手段６にて生成されたラバーバンドは表示位置算出手段７にてこれらの表示位置が算出された後、表示手段２に送られ、画面表示される。また、表示位置算出手段７では、特定点生成手段５にて生成された図形要素の持つすべての特定点の内、カーソルに最も近い特定点を算出して、表示手段２に強調表示を指示するようにしている。
【００３９】
図１５は本発明を実施するためのワークステーションのハードウエア構成の一例を示す図である。図において、ワークステーションは、プロセッサ１１と、読み取り専用メモリ（ＲＯＭ）１２と、メインメモリ（ＲＡＭ）１３と、グラフィック制御回路１４及び表示装置１５と、マウス１６と、キーボード１７と、タブレット１８と、ハードディスク装置（ＨＤＤ）１９と、磁気テープ装置（ＭＴＤ）２０と、プロッタ２１と、プリンタ２２と、カラーハードコピー２３とで構成され、これらの構成要素はそれぞれのインタフェースコントローラ（図示していない）及びバス２４により相互に結合されている。
【００４０】
プロセッサ１１はワークステーション全体を統括的に制御する。読み取り専用メモリ１２にはたとえば立ち上げ時に必要なプログラムなどが格納されている。メインメモリ１３にはシステムプログラム、ＣＡＤシステムのアプリケーションプログラムなどが展開されている他に、作図あるいは編集中のデータなどが生成、格納される。
【００４１】
グラフィック制御回路１４はフレームメモリなどを有し、メインメモリ１３内で生成された２次元の線分データ、円データ、円弧データなどの各種図形要素データを表示信号に変換し、表示装置１５に送る。表示装置１５は、受けた表示信号を基に図形要素から成る図面を表示する。
【００４２】
マウス１６は表示装置１５の画面上に表示されているカーソルを移動させ、ボタンをクリックすることによって画面上に表示されている図形要素をヒットしたり、各種メニューなどの選択を指示するポインティングデバイスである。キーボード１７は検索範囲の値などの数値データなどを入力するのに使用される。タブレット１８は図面を作成するときなどの座標入力に使用される。
【００４３】
ハードディスク装置１９は、システムプログラム、ＣＡＤシステムのアプリケーションプログラム、製図に必要な各種図形要素データ、検索範囲設定テーブルなどが格納されている。磁気テープ装置２０は磁気テープ２０ａに記憶されている設計図などのデータを入力したり、作成された設計図などのデータを磁気テープ２０ａに記憶させることができる外部記憶装置である。
【００４４】
また、作成された設計図のデータは、プロッタ２１、プリンタ２２又はカラーハードコピー２３に出力し出図することができる。
【００４５】
【発明の効果】
以上説明したように本発明では、第１の位置を中心として、円をラバーバンドで表示し、第２の位置をヒットして、中心と第２の位置を半径とする円を創成し、さらにその円の中心及び半径を決めた位置及びカーソルの位置によって決まる円をラバーバンドで表示し、第３の位置をヒットして、円の中心及び半径を決めた位置及びカーソルの位置によって決まる円を創成するようにしたので、円の半径を自由に伸縮でき、他の図形との関連において、簡単に求める円を創成できる。
【図面の簡単な説明】
【図１】ナビゲーション表示方法のフローチャートである。
【図２】特定点を求める処理の詳細を示すフローチャートである。
【図３】直線の特定点を求める処理の詳細を示すフローチャートである。
【図４】円の特定点を求める処理の詳細を示すフローチャートである。
【図５】円の特定点を求める処理によって求められた特定点を表す図である。
【図６】円弧の特定点を求める処理の詳細を示すフローチャートである。
【図７】円弧の特定点を求める処理によって求められた特定点を表す図である。
【図８】線分創成の場合の特定点表示の例を示す図である。
【図９】円創成の場合の特定点表示の例を示す図である。
【図１０】円弧創成の場合の特定点表示の例を示す図である。
【図１１】２次元の線分及びそのデータ形式を示した図である。
【図１２】２次元の円及びそのデータ形式を示した図である。
【図１３】２次元の円弧及びそのデータ形式を示した図である。
【図１４】ナビゲーション表示装置の原理を示した構成図である。
【図１５】本発明を実施するためのワークステーションのハードウエア構成の一例を示す図である。
【符号の説明】
１ 図形要素情報記憶手段
２ 表示手段
２ａ 表示制御手段
２ｂ 表示情報記憶手段
２ｃ 表示部
３ カーソル情報認識手段
４ 図形要素検索手段
５ 特定点生成手段
６ ラバーバンド生成手段
７ 表示位置算出手段
１１ プロセッサ
１２ 読み取り専用メモリ
１３ メインメモリ
１４ グラフィック制御回路
１５ 表示装置
１６ マウス
１７ キーボード[0001]
[Industrial application fields]
The present invention relates to a method for creating a circle as a graphic element, and more particularly to a method for creating a circle for creating a circle related to a graphic element already created in an interactive system such as a CAD (computer aided design) system.
[0002]
In a 2D CAD system, drawings such as design drawings can be freely drawn on the screen of a graphic display using basic graphic elements such as straight lines, circles and arcs, and the drawn drawings can be edited. When the drawing is completed on the screen, it can be output as a drawing by a plotter or the like, or the completed drawing can be stored in a storage medium for later use.
[0003]
[Prior art]
In a 2D CAD system, for example, when creating a circle, a circle can be easily drawn by a command from a keyboard or an input from a digitizer. However, by using a mouse, a circle can be created or a created circle can be created. Operations such as moving and editing can be performed more intuitively.
[0004]
[Problems to be solved by the invention]
On the other hand, in the conventional navigation display function, a circle is generally created by a method such as specifying a center and a point on the circumference, and a circle corresponding to an already created graphic element is created. Requires complicated operations.
[0005]
The present invention has been made in view of the above points, and an object of the present invention is to provide a circle creation method that can easily create a circle in a drawing operation of a two-dimensional CAD system.
[0006]
[Means for Solving the Problems]
FIG. 9 is a diagram illustrating the principle of the method of the present invention that achieves the above object. As shown in FIG. 9, the center of the first circle is determined by hitting the first position P1. A first circle C1 having a radius from the position P1 to the cursor position is displayed in a rubber band, and an arbitrary second position P2 By hitting the first circle C1 And then The second circle C2 determined by the first position P1, the second position P2 and the cursor position is displayed in a rubber band, and a second circle C2 designated by three points by hitting an arbitrary third position And finally the second circle Circle by confirming operation C2 Confirm.
[0007]
[Action]
The center of the circle is determined, and a circle with a radius that is the distance between the center of the circle and the cursor position is displayed as a rubber band. Then, a first circle is created by designating a radius, and a second circle determined by the position of the center and radius of the first circle and the position of the cursor is displayed in a rubber band. By doing so, it is possible to freely expand and contract the circle, and to easily create a desired circle in relation to other figures.
[0008]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a flowchart of the navigation display method. Details of the navigation display method will be described based on the flowchart of FIG.
[0009]
In the navigation display method, first, a search range is acquired from a search range setting table (step S1). The search range is, for example, a rectangular range set around the cursor position, and can be arbitrarily set by the user. For example, when “5” is set in the search range setting table, a 5 mm square search range is set around the cursor position, and a graphic element is searched within the search range.
[0010]
Next, the current cursor position is acquired (step S2). The current cursor position can be obtained based on movement information from the mouse. Next, the graphic element in the search range centered on the current cursor position obtained in step S2 is searched, and the identifier (ID) of the searched graphic element is acquired (step S3).
[0011]
Next, all the specific points of the graphic element obtained in step S3 are obtained (step S4). Here, all the characteristic points of the graphic element are obtained according to the obtained graphic element. Next, all the specific points obtained in step S4 are displayed on the screen (step S5).
[0012]
Then, from the positional relationship between all the specific points obtained in step S4 and the position of the cursor, a specific point closest to the cursor is obtained from those specific points (step S6), and the specific point is highlighted (step). S7). The highlighting of the nearest specific point is performed in such a way that it can be distinguished from other specific points. For example, highlighting is performed by highlighting the display graphic representing the specific point, changing it to another display graphic, or changing it to another conspicuous color.
[0013]
Such a series of processing is repeatedly executed every 30 milliseconds, for example.
FIG. 2 is a flowchart showing details of processing for obtaining a specific point. According to FIG. 2, in the process for obtaining a specific point, it is determined whether or not the searched graphic element is a straight line (step S11). In this step S11, it is determined from the obtained graphic element identifier whether there is a type number representing a straight line in the data representing the graphic element. If the graphic element is a straight line, the process proceeds to a process for obtaining a specific point of the straight line. All the specific points on the straight line are obtained (step S12).
[0014]
Next, it is determined whether or not the obtained graphic element is a circle (step S13). If there is a type number representing a circle in the data representing the graphic element from the obtained graphic element identifier, the process proceeds to a process for obtaining a specific point of the circle, and all the specific points of the circle are obtained (step S14). If there is no type number representing a circle, that is, if the figure is an arc, the process proceeds to a process for obtaining a specific point of the arc, and all the specific points of the arc are obtained (step S15).
[0015]
In addition, as an example of the process for obtaining a specific point, the graphic element is limited to a straight line, a circle, and an arc for the sake of simplicity, but actually, other graphic elements such as a rectangle and an ellipse are actually used. All specific points are also required.
[0016]
FIG. 3 is a flowchart showing details of processing for obtaining a specific point on a straight line. As shown in FIG. 3, in the process of obtaining a specific point of a straight line, first, both end points of the straight line are obtained (step S21), and then the midpoint of the straight line is obtained (step S22). As a result, both end points and midpoints of the straight line, which are specific points of the straight line, are obtained.
[0017]
FIG. 4 is a flowchart showing details of processing for obtaining a specific point of a circle. As shown in FIG. 4, in the process of obtaining the specific point of the circle, first, the center point of the circle is obtained (step S31). Next, the vertex of the circle, that is, the point where the circle intersects with the line in the x-axis direction and the y-axis direction passing through the center point (step S32). Next, it is determined whether or not another point is designated in advance (step S33). That is, in order to create a certain graphic element, for example, a straight line segment, it is determined whether the starting point of the line segment has been hit in advance. In step S33, if the cursor is simply moved before entering the procedure for creating a graphic element, all the specific points of the circle have been obtained. If the point is hit, a contact point on the circumference with the graphic element being created displayed in the rubber band is obtained as a specific point (step S34).
[0018]
FIG. 5 is a diagram illustrating specific points obtained by processing for obtaining specific points of a circle. According to this figure, if there is a circle C that has already been drawn and this circle C is included in the search range centered on the cursor, a specific point of the circle C will be shown in accordance with the circle processing flowchart shown in FIG. Is required. First, the center point p1 of the circle C is obtained, and then the vertices p2, p3, p4, and p5 on the circumference are obtained. Here, for example, if the start point of the line segment has already been hit at the position P indicated by “x” in order to create a straight line segment, the position P is set as the start point and “+ A line segment R temporarily displayed with the position indicated by “” as an end point is displayed in a rubber band. If the cursor has approached this circle C, the processing for obtaining a specific point has started, and if the center point p1 of the circle C and the vertices p2, p3, p4, p5 on the circumference have already been obtained, The points of contact p6 and p7 when the straight line segment to be created contacts the circle C are obtained as specific points and displayed on the screen. In this way, in the process of obtaining the specific points of the circle, all the specific points p1 to p7 that can be taken with respect to the circle C are obtained. Thereafter, the specific point closest to the cursor, in the example shown, the specific point p3 is obtained and highlighted on the screen.
[0019]
FIG. 6 is a flowchart showing details of processing for obtaining a specific point of an arc. As shown in FIG. 6, in the process of obtaining the specific point of the arc, first, the center point of the arc is obtained (step S41). Next, both end points of the arc are obtained (step S42), and a vertex on the arc, that is, a point where the arc intersects with the line in the x-axis direction and the y-axis direction passing through the center point (step S43). Next, it is determined whether another point has been designated in advance (step S44). That is, it is determined whether some other point has already been hit in order to create a certain graphic element. In step S44, if the cursor is simply moved before entering the procedure for creating a graphic element, all the specific points of the arc have been obtained. If another point is hit, a contact point on the arc of the created graphic element displayed in the rubber band and the arc is obtained as a specific point (step S45).
[0020]
FIG. 7 is a diagram showing the specific points obtained by the process for obtaining the specific points of the arc. According to this figure, when there is an already drawn arc A and this arc A is included in the search range centered on the cursor, the specific point of the arc A is determined according to the arc processing flowchart shown in FIG. Is required. First, the center point p1 of the arc A is obtained, and then both end points p2 and p3 of the arc A and vertices p4 and p5 on the arc are obtained. Here, for example, if the start point of the line segment has already been hit at the position P indicated by “x” in order to create a straight line segment, the position P is set as the start point and “+ A line segment R temporarily displayed with the position indicated by “” as an end point is displayed in a rubber band. If the cursor has approached the arc A, the process for obtaining a specific point has started. If the specific points p1, p2, p3, p4, and p5 of the arc A have already been obtained, the next attempt is to create them. A contact point p6 when the straight line segment contacts the arc A is obtained as a specific point and displayed on the screen. As described above, in the process for obtaining the specific point of the arc, all the specific points p1 to p6 that can be taken with respect to the arc A are obtained. Thereafter, the specific point closest to the cursor, in the example shown, the specific point p3 is obtained and highlighted on the screen.
[0021]
FIG. 8 is a diagram showing an example of specific point display in the case of line segment creation.
On the screen, for example, three line segments L1, L2, and L3 and a circle C are drawn in the center, and a line segment starting from the end point of the line segment L1 is created. The case will be described. When a position P1 indicated by “x” is first hit, a temporary line segment R starting from the position P1 and ending at the cursor position is displayed in a rubber band. The provisional line segment R displayed in the rubber band is indicated by a broken line in the drawing. Next, when the cursor is moved from there, the cursor approaches the circle C, and a part of the circle C is searched within the search range centered on the cursor of the graphic element set in advance. The graphic element that is the circle C is detected. Then, the specific point which this circle C has is displayed. In the illustrated example, a black circle display marker representing a specific point is displayed. As specific points in the case of a circle, a center point of the circle, four vertices on the circumference, and a contact point on the circumference are displayed. Here, for example, when the cursor is brought near the center point of the circle C indicated by “•”, the center point is recognized as a specific point closest to the cursor, and the center point is highlighted, for example, shown in the figure. In the example, a double circle is displayed. Moreover, in addition to the display of this specific point, the result when a line is drawn between the position P1 and the center point of the circle is displayed in a rubber band, so that the user has a double point at the center point. If you hit when you are, you can see that this center point is the other end of the straight line you are trying to create.
[0022]
If a tangent line is drawn with respect to the circle C, when the cursor is moved to the vicinity of the contact position of the circle C, a specific point displayed at a position to be a contact point on the circumference is highlighted. As a result, when a tangent line is drawn on the circle C with the line segment starting from the position P1, the position to be hit for specifying the end point of the line segment is displayed in advance as a guide, and the tangent line is displayed. A rough result of the line segment when it is drawn will be displayed in a rubber band. Of course, when the cursor leaves the circle C, the displayed specific point is erased from the screen.
[0023]
Next, if you move the cursor and move it to the position of “•”, for example, in the area where there is no graphic element nearby, there is no graphic element originally written around this area, so no graphic element is detected. In this case, as usual, the position of the cursor indicated by “+” represents the end point of the line segment to be created, and the rubber band display line segment will be drawn here as it is. I understand.
[0024]
Next, when the cursor is brought close to the vicinity of the line segment L3, this time, the line segment L3 is detected, and a specific point of the line segment is displayed. There are three specific points of the line segment, the two end points and the center point. When the cursor is moved near one end point of the line segment L3 indicated by “•”, the specific point at the position “•” is highlighted among the three specific points. Therefore, when the end point of the line segment starting from the position P1 is set as one end point of the line segment L3, it is only necessary to hit the specific point highlighted, and the connection line with the existing line segment Creation can be facilitated.
[0025]
FIG. 9 is a diagram showing an example of specific point display in the case of circle creation.
For example, a case where one line segment L4 is already drawn on the screen and a circle is created near the line segment L4 or a tangent circle is created for the line segment L4 will be described. When the position P1 is first hit, a temporary display circle C1 appears with the position P1 as the center. The circle C1 is displayed in a rubber band with the position P1 as the center and the cursor position as one point on the circumference. Accordingly, the radius C1 of the temporary display is freely changed with the movement of the cursor with the position P1 as the center, and it is possible to know in advance how large the circle can be drawn. Next, when the position P2 is hit, a circle C1 determined by the center of the position P1 and a radius corresponding to the distance from the position P1 to the position P2 is created, and can be distinguished from other graphic elements as a temporary display circle. Is displayed. For example, if a confirmed graphic element is displayed in green, it is displayed in a different color, for example, yellow. Here, if it is desired to create a circle specified by the center and the radius, at this point, for example, by pressing a key representing confirmation, creation of the circle C1 is confirmed, and the display color of the graphic element whose display color is also confirmed is determined. Change to color.
[0026]
When the circle C1 is displayed as a temporarily displayed circle in a color different from that of other graphic elements, that is, before the circle C1 is fixed, if the cursor is further moved, 3 of the positions P1 and P2 and the cursor position The circle C2 determined by the points is displayed in a rubber band, and the process moves to creation of a circle by specifying three points. This circle C2 is also displayed in a form that can be distinguished from other graphic elements, for example, with a white dotted line. At this time, when the cursor approaches the already drawn line segment L4, a specific point of the line segment L4, that is, the center of the line segment L4 and its both end points are displayed, and a guide display for designating the third point Is made. When creating a tangent circle for the line segment L4, the third point on the line segment L4 is moved by moving the cursor over the line segment L4 while looking at the circle C2 displayed in the rubber band. You can easily find and specify.
[0027]
FIG. 10 is a diagram showing an example of specific point display in the case of arc generation.
For example, two line segments L5 and L6 have already been drawn on the screen, and arc generation when these line segments are connected by an arc will be described. When the cursor is first moved to the vicinity of the line segment L5 in order to determine one end point of the arc, the line segment L5 is detected, and the specific points of the line segment L5, that is, both end points and the center thereof are displayed. Since the position to be the starting point of the arc to be created is displayed in advance by a specific point, and the specific point close to the cursor is highlighted, it is very easy to find and hit the position P1. Subsequently, when the cursor is moved to the vicinity of the line segment L6 in order to determine the other end point of the arc, the line segment L6 is detected, and three specific points of the line segment L6 are displayed. Is highlighted. Among these, a line connecting the position P1 and the position P2 is displayed by hitting when the position P2 is highlighted. Thereafter, the position of the cursor is the third position for determining the arc, and each time the cursor is moved, the arc A passing through these three points is displayed in a rubber band. When the desired arc A is displayed in the rubber band, the third point for specifying the arc is determined by hitting the cursor position P3, and the arc A is determined.
[0028]
FIG. 11A is a diagram representing a two-dimensional line segment, and FIG. 11B is a diagram illustrating a data format of a graphic element of the line segment. As shown in these figures, the two-dimensional line segment includes the coordinates (x0, y0) of the start point of the line segment and the direction unit vector of the line segment.
[0029]
[Outside 1]

[0030]
And the length l of the line segment. Of these, the direction unit vector of the line segment uses the unit vector a in the x-axis direction and the unit vector b in the y-axis direction,
[0031]
[Expression 1]

[0032]
Therefore, the data indicating the graphic element of the line segment is represented by x0, y0, a, b and l, and is held in the format as shown in FIG. The top of the data is a type number representing the type of graphic element. For example, “2” is assigned to a two-dimensional line segment. A graphic element identifier (ID) uniquely determined when a graphic is drawn represents the head address of data having this type number. The length of the line segment is l> 0, but when l = 0, it represents an infinite line and l · 16.0 × 10 ³¹ (The square root of the maximum real value) represents a semi-infinite line.
[0033]
FIG. 12A is a diagram representing a two-dimensional circle, and FIG. 12B is a diagram illustrating a data format of a graphic element of a circle. As shown in these drawings, the two-dimensional circle can be represented by the coordinates (x, y) of the center position and the radius r. In order to make the data format the same as in the case of the arc, the data indicating the graphic element of the circle is added with a relative angle θ2 (in radians) to the start angle θ1 and the end point, and in FIG. Stored in the format shown. In the case of a circle, the starting angle θ1 is stored as “0”, and the relative angle θ2 to the end point is stored as “2π”. For example, “5” is assigned as a type number to the two-dimensional circle.
[0034]
FIG. 13A is a diagram representing a two-dimensional arc, and FIG. 13B is a diagram showing a data format of a graphic element of the arc. As shown in these drawings, the two-dimensional arc can be represented by the coordinates (x, y) of the center position, the radius r, the start angle θ1, and the relative angle θ2 to the end point. The starting angle θ1 is
[0035]
[Expression 2]
-2π <θ1 ≦ 2π (2)
The relative angle θ2 to the end point is
[0036]
[Equation 3]
-2π ≦ θ2 ≦ 2π (θ2 ≠ 0) (3)
Takes the value of The rotation direction of the arc is counterclockwise when the relative angle to the end point is θ2> 0, and clockwise when θ2 <0. For example, “6” is assigned as a type number to the two-dimensional arc.
[0037]
FIG. 14 is a block diagram showing the principle of the navigation display device. According to this figure, the navigation display device has graphic element information storage means 1 for storing information on graphic elements of straight lines, circles and arcs, and the display means 2 is connected to the graphic element information storage means 1. A graphic based on the read information is displayed. The display means 2 includes a display control means 2a for converting graphic element information stored in the graphic element information storage means 1 into display information, a display information storage means 2b for storing the display information, and this display information storage means 2b. And a display unit 2c for displaying the display information stored therein. The navigation display device further includes cursor information recognition means 3 for recognizing the search range of the graphic elements, the current position and the hit position of the cursor, and a graphic element close to the current position of the cursor among the graphic elements being displayed on the display means 2. The graphic element search means 4 to be searched, the specific point generation means 5 for generating a specific point of the graphic element from the graphic element searched by the graphic element search means 4, the hit position of the cursor from the cursor information recognition means 3, A rubber band generating means 6 for temporarily generating a graphic element to be created from the current position, a specific point generated by the specific point generating means 5 and a display position of the rubber band generated by the rubber band generating means 6 And display position calculation means 7 for calculating. Although not shown, the display position calculation unit 7 calculates a specific point closest to the cursor among all the specific points of the graphic element generated by the specific point generation unit 5 and displays the specific point on the display unit 2. Means for instructing highlighting is provided.
[0038]
According to the illustrated navigation display apparatus, the graphic element information storage means 1 stores information on graphic elements created in the CAD system. The display means 2 displays a graphic element based on this graphic element information. In the display means 2, the display control means 2a converts the graphic element information stored in the graphic element information storage means 1 into display information, the display information is stored in the display information storage means 2b, and is displayed on the display unit 2c. Display information stored in the information storage means 2b is displayed. The cursor information recognizing means 3 recognizes the graphic element search range centered on the cursor, the current position of the cursor, and the hit position obtained by clicking the mouse button. The graphic element search means 4 searches the graphic element being displayed on the display means 2 for a graphic element close to the current position of the cursor, that is, a graphic element within the search range. The specific point generation means 5 generates a specific point of the graphic element from the graphic element searched by the graphic element search means 4, and the rubber band generation means 6 generates the hit position and the current position of the cursor from the cursor information recognition means 3. Temporarily generate a graphic element to be created based on. The specific points generated by the specific point generation means 5 and the rubber bands generated by the rubber band generation means 6 are sent to the display means 2 after their display positions are calculated by the display position calculation means 7. Is displayed on the screen. Further, the display position calculation means 7 calculates a specific point closest to the cursor among all the specific points of the graphic element generated by the specific point generation means 5 and instructs the display means 2 to perform highlighting. I am doing so.
[0039]
FIG. 15 is a diagram showing an example of a hardware configuration of a workstation for carrying out the present invention. In the figure, the workstation includes a processor 11, a read only memory (ROM) 12, a main memory (RAM) 13, a graphic control circuit 14 and a display device 15, a mouse 16, a keyboard 17, a tablet 18, A hard disk device (HDD) 19, a magnetic tape device (MTD) 20, a plotter 21, a printer 22, and a color hard copy 23, and these components are respectively interface controllers (not shown) and The buses 24 are connected to each other.
[0040]
The processor 11 comprehensively controls the entire workstation. The read-only memory 12 stores, for example, programs necessary for startup. In addition to system programs and CAD system application programs being developed, the main memory 13 generates and stores data being drawn or edited.
[0041]
The graphic control circuit 14 has a frame memory and the like, converts various graphic element data such as two-dimensional line segment data, circle data, and arc data generated in the main memory 13 into display signals and sends them to the display device 15. . The display device 15 displays a drawing composed of graphic elements based on the received display signal.
[0042]
The mouse 16 is a pointing device that moves a cursor displayed on the screen of the display device 15 and hits a graphic element displayed on the screen by clicking a button or instructs selection of various menus. is there. The keyboard 17 is used to input numerical data such as a search range value. The tablet 18 is used for inputting coordinates when creating a drawing.
[0043]
The hard disk device 19 stores a system program, a CAD system application program, various graphic element data necessary for drawing, a search range setting table, and the like. The magnetic tape device 20 is an external storage device that can input data such as a design drawing stored in the magnetic tape 20a and store data such as a created design drawing in the magnetic tape 20a.
[0044]
The created design drawing data can be output to the plotter 21, printer 22 or color hard copy 23 for output.
[0045]
【The invention's effect】
As described above, in the present invention, a circle is displayed with a rubber band centered on the first position, a second position is hit, and a circle having a radius between the center and the second position is created. Further, the circle determined by the position where the center and radius of the circle are determined and the position of the cursor is displayed in a rubber band, the third position is hit, and the position where the center and radius of the circle are determined and the position of the cursor Creating a determined circle As a result, the radius of the circle can be freely expanded and contracted, and a desired circle can be easily created in relation to other figures.
[Brief description of the drawings]
FIG. 1 is a flowchart of a navigation display method.
FIG. 2 is a flowchart showing details of processing for obtaining a specific point.
FIG. 3 is a flowchart showing details of a process for obtaining a specific point of a straight line.
FIG. 4 is a flowchart showing details of processing for obtaining a specific point of a circle.
FIG. 5 is a diagram illustrating specific points obtained by processing for obtaining specific points of a circle.
FIG. 6 is a flowchart showing details of processing for obtaining a specific point of an arc.
FIG. 7 is a diagram illustrating specific points obtained by processing for obtaining a specific point of an arc.
FIG. 8 is a diagram illustrating an example of specific point display in the case of line segment creation.
FIG. 9 is a diagram illustrating an example of specific point display in the case of circle creation.
FIG. 10 is a diagram illustrating an example of specific point display in the case of arc generation.
FIG. 11 is a diagram showing a two-dimensional line segment and its data format.
FIG. 12 is a diagram showing a two-dimensional circle and its data format.
FIG. 13 is a diagram showing a two-dimensional arc and its data format.
FIG. 14 is a configuration diagram showing the principle of a navigation display device.
FIG. 15 is a diagram illustrating an example of a hardware configuration of a workstation for carrying out the present invention.
[Explanation of symbols]
1 Graphic element information storage means
2 Display means
2a Display control means
2b Display information storage means
2c Display section
3 Cursor information recognition means
4 Graphic element search means
5 Specific point generation means
6 Rubber band generation means
7 Display position calculation means
11 processor
12 Read-only memory
13 Main memory
14 Graphic control circuit
15 Display device
16 mice
17 Keyboard

Claims (1)

In the circle creation method that creates a circle using the mouse cursor,
Determine the center position of the first circle by hitting any first position displayed with the cursor,
The first circle with the first position as the center and the cursor position as the radius from the center position is displayed in a rubber band,
Creating the first circle of center and radius designation by hitting any second position;
A second circle determined by the first position, the second position, and the cursor position is displayed in a rubber band, and by hitting an arbitrary third position, the second circle designated by three points is displayed. Create
Confirm the created circle,
A circle creation method characterized by comprising steps.

Images