初めて、質問させていただきます。 添付画像では、赤丸の位置にマウスがあり、描画した円の中心からマウス座標に向かって 白線を引いています。 以下、描画コードの抜粋, source -> http://kie.nu/1utH ------------------------- // static static final int X = 2; static final int Y = 2; static final Dimension DEFAULT = new Dimension(WIDTH, HEIGHT); static final doubleSIZE= 32; static final InsetsDAMMY= new Insets(0, 0, 0, 0); // instance Rectangle2D.Double r2d = new Rectangle2D.Double(); Ellipse2D.Double e2d = new Ellipse2D.Double(); Arc2D.Double a2d = new Arc2D.Double(); Line2D.Double l2d = new Line2D.Double(); BasicStroke std_stroke_05 = new BasicStroke(0.5f); BasicStroke std_stroke = new BasicStroke(1.2f); BasicStroke std_stroke2 = new BasicStroke(2.0f); Image off_img; protected Graphics2D getOffScreenPen() { Image img = this.off_img; if(img == null) { img = super.createImage(super.getWidth(), super.getHeight()); this.off_img = img; } return (Graphics2D)img.getGraphics().create(); } protected void paintComponent(Graphics g) { int width = super.getWidth(); int height = super.getHeight(); Insets its = super.getInsets(); int start_x = 0, start_y = 0; if(its != null) { start_x = its.left; start_y = its.top; } else its = DAMMY; Graphics2D g2 = this.getOffScreenPen(); super.paintBorder(g2); g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_NORMALIZE); g2.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_SPEED); g2.setPaint( Color.black ); g2.fillRect(start_x, start_y, width - (its.left + its.right), height - (its.top + its.bottom)); // test. test(g2, SIZE, start_x, start_y, width - (its.left + its.right), height - (its.top + its.bottom), DRAW_MOUSE_TO_ELEMENT_CENTER ); g.drawImage(this.off_img, 0, 0, this); g2.dispose(); g.dispose(); } static final int DRAW_MOUSE_TO_ELEMENT_CENTER = 0; static final int DRAW_MOUSE_TO_ELEMENT_CENTER_2 = 1; public void test(Graphics2D g2, double size, int start_x, int start_y, int width, int height, int id) { int count_x, arry_size; start_x += X; start_y += Y; int start_x_cache = start_x; double unit = size + X * 2; count_x = (int)(width - (X * 2)); count_x = (int)(count_x / unit); arry_size = (int)(height - (Y * 2)); arry_size = (int)(arry_size / unit) * count_x; for(int i = 0, x_index = 0; i < arry_size; i++) { int r = (int)(Math.random() * 255); int g = (int)(Math.random() * 255); int b = (int)(Math.random() * 255); drawOvalDouble(g2, new Color(r, g, b), start_x, start_y, size, id); start_x += unit; if(++x_index > count_x - 1) { x_index = 0; start_y += unit; start_x = start_x_cache; } } } // draw oval by size. public void drawOvalDouble(Graphics2D g, Color color, double x, double y, double size, int id) { g.setStroke(std_stroke); // fill oval g.setPaint(color); e2d.setFrame(x + 2.4D, y + 2.4D, size - 3.6D, size - 3.6D); g.fill(e2d); // draw highlight oval g.setPaint(Color.white); e2d.setFrame(x, y, size, size); g.draw(e2d); // draw highlight down oval g.setPaint(Color.white.darker()); e2d.setFrame(x + 1.2D, y + 1.2D, size - 1.8D, size - 1.8D); g.draw(e2d); // draw highlight double add_x = size * (size < 10? 0.3D: size < 17? 0.2D: 0.15D); g.setStroke(std_stroke2); a2d.setArc(x + add_x, y + add_x, size - (add_x * 2), size - (add_x * 2), 115D, 30D, Arc2D.OPEN); g.setPaint(Color.white); g.draw(a2d); if(id == DRAW_MOUSE_TO_ELEMENT_CENTER) { double r = size / 2; l2d.setLine(x + r, y + r, this.mouse_x, this.mouse_y); g.setStroke(std_stroke_05); //g.setPaint(color.brighter()); g.draw(l2d); } else if(id == DRAW_MOUSE_TO_ELEMENT_CENTER_2) { ; } } ------------------------------------------------ これは2点間に線を描画するだけなので簡単なのですが、新しいテストとして円の中心からマウス座標までの 直線をtest2のように描画するコードを書きたいのです。 数学はあまり得意ではなく、いろいろググっては見ましたがピンときませんでした。 ヒントとなる数式でもご教授いただけないでしょうか？ どうぞよろしくお願いします。
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