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积少成多Flash(6) - ActionScript 3.0 绘图之图形和转换


作者：webabcd


介绍
演示使用 Flash ActionScript 3.0 画一些基本的图形，以及对绘制的图形或其他可视对象做一些基本的转换
  • 画图 - 通过 Shape 对象的 graphics 属性来执行矢量绘图命令
    • 1、使用 lineStyle() 定义画图的线条样式
    • 2、moveTo() - 设置当前绘画点；lineTo() - 以当前绘画点为起点，用当前定义的线条样式，画一条直线到目标点；curveTo() - 指定二次贝塞尔曲线的控制点和终点，从而完成曲线的绘制；drawRect() - 绘制矩形；drawCircle() - 绘制圆形；drawEllipse() - 绘制椭圆；
    • 3、beginFill() 和 endFill() 用于填充他们之间所绘制的图形。如果是渐变填充则对应的方法是 beginGradientFill 和 endFill()
  • 转换 - 通过设置对象的 transform.matrix 属性，对其做相应的转换
    • Matrix.rotate() - 旋转的角度
    • Matrix.translate() - 平移的距离
    • Matrix.scale() - 缩放的比例
    • Matrix.b - 将矩阵垂直倾斜
    • Matrix.c - 将矩阵水平倾斜


1、画图
在 UI 上放置 8 个 Button
名称分别为：btnLine, btnCurve, btnRectangle, btnCircle, btnEllipse, btnLiner, btnRadial, btnClea
分别用于演示：画直线，画曲线，画矩形，画圆形，画椭圆，线性渐变填充，放射性渐变填充，清除图形
Main.as
package    
{
        import flash.display.MovieClip;
        import fl.events.ComponentEvent;
        import fl.events.SliderEvent;
        import flash.display.Shape;
        import flash.geom.Matrix;
        import flash.display.GradientType;
        import flash.display.SpreadMethod;
        
        public class Main extends MovieClip
        {
                var originalMatrix:Matrix;
                
                public function Main():void
                {
                        btnLine.addEventListener(ComponentEvent.BUTTON_DOWN, drawLine);
                        btnCurve.addEventListener(ComponentEvent.BUTTON_DOWN, drawCurve);
                        btnRectangle.addEventListener(ComponentEvent.BUTTON_DOWN, drawRectangle);
                        btnCircle.addEventListener(ComponentEvent.BUTTON_DOWN, drawCircle);
                        btnEllipse.addEventListener(ComponentEvent.BUTTON_DOWN, drawEllipse);
                        btnLiner.addEventListener(ComponentEvent.BUTTON_DOWN, drawLinerGradient);
                        btnRadial.addEventListener(ComponentEvent.BUTTON_DOWN, drawRadialGradient);
                        btnClear.addEventListener(ComponentEvent.BUTTON_DOWN, clearGraphics);
                }
                
                
                // 画直线
                function drawLine(e:ComponentEvent):void    
                {
                        // lineStyle() - 定义画图的线条样式
                        //         第一个参数：线条粗细，整数（0 - 255）
                        //         第二个参数：线条的颜色值（16进制）
                        //         第三个参数：不透明度（0 - 1）
                        canvas.graphics.lineStyle(12, 0x000000);
                        
                        // moveTo() - 设置当前绘画点。在本例中就是直线的起点
                        canvas.graphics.moveTo(0, 0);
                        
                        // lineTo() - 以当前绘画点为起点，用当前定义的线条样式，画一条直线到目标点
                        canvas.graphics.lineTo(100, 100);
                }
                
                // 画曲线（二次贝塞尔曲线）
                function drawCurve(e:ComponentEvent):void    
                {
                        canvas.graphics.lineStyle(1, 0x000000);
                        canvas.graphics.moveTo(100, 0);
                        
                        // curveTo() - 指定二次贝塞尔曲线的控制点和终点，从而完成曲线的绘制
                        //         前两个参数为控制点，后两个参数为终点，当前绘画点为起点
                        canvas.graphics.curveTo(100, 100, 200, 200);
                }
                
                // 画矩形
                function drawRectangle(e:ComponentEvent):void    
                {
                        canvas.graphics.lineStyle(5, 0xFF0000);
                        
                        // drawRect() - 绘制矩形
                        //         第一个参数：矩形左上角的 x 坐标
                        //         第二个参数：矩形左上角的 y 坐标
                        //         第三个参数：矩形的宽
                        //         第四个参数：矩形的高
                        canvas.graphics.drawRect(200, 0, 100, 50);
                }
                
                // 画圆
                function drawCircle(e:ComponentEvent):void    
                {
                        canvas.graphics.lineStyle(1, 0x000000);
                        
                        // beginFill() - 单色填充这之后所绘制的图形，直到调用endFill()为止
                        //         两个参数分别为填充的颜色值和不透明度
                        canvas.graphics.beginFill(0xFF0000, 0.5);
                        
                        // drawCircle() - 绘制圆形
                        //         三个参数分别为圆心的 x 坐标，圆心的 y 坐标，圆形的半径
                        canvas.graphics.drawCircle(300, 0, 30);
                        
                        // endFill() - 呈现 beginFill() 与 endFill() 之间所绘制的图形的填充效果
                        canvas.graphics.endFill();
                }        
                
                // 画椭圆
                function drawEllipse(e:ComponentEvent):void    
                {
                        canvas.graphics.lineStyle(1, 0x000000);
                        canvas.graphics.beginFill(0xFF0000);
                        
                        // drawEllipse() - 绘制椭圆
                        //         前两个参数：椭圆左侧顶点的 x 坐标和 y 坐标
                        //         后两个参数：椭圆的宽和高
                        canvas.graphics.drawEllipse(0, 200, 100, 50);
                        
                        canvas.graphics.endFill();
                }
                
                // 线性渐变填充
                function drawLinerGradient(e:ComponentEvent):void    
                {
                        canvas.graphics.lineStyle(1, 0x000000);
                        
                        // 声明一个仿射矩阵 Matrix
                        var gradientBoxMatrix:Matrix = new Matrix();
                        
                        // createGradientBox() - Matrix 的一个专门为渐变填充提供的方法
                        //         三个参数分别为渐变框的宽，渐变框的高，渐变框的旋转弧度
                        gradientBoxMatrix.createGradientBox(50, 20, 0);
                        
                        // beginGradientFill() - 做渐变填充
                        //         第一个参数：渐变模式。GradientType.LINEAR为线性渐变；GradientType.RADIAL为放射性渐变
                        //         第二个参数：渐变色的颜色值数组
                        //         第三个参数：渐变色的不透明度数组
                        //         第四个参数：渐变色的分布比例数组（0 - 255）。0为渐变框的最左侧，255为渐变框的最右侧
                        //         第五个参数：用 Matrix.createGradientBox() 生成的渐变框
                        //         第六个参数：伸展方式    
                        //                 SpreadMethod.PAD - 用线性渐变线末端的颜色值填充剩余空间
                        //                 SpreadMethod.REFLECT - 相邻填充区域，以 相反方向 重复渐变，直至填充满整个剩余空间
                        //                 SpreadMethod.REPEAT - 相邻填充区域，以 相同方向 重复渐变，直至填充满整个剩余空间
                        canvas.graphics.beginGradientFill(GradientType.LINEAR, [0xFF0000, 0x0000FF], [1, 1], [0, 255], gradientBoxMatrix, SpreadMethod.REPEAT);
                        
                        canvas.graphics.drawRect(100, 200, 100, 20);
                        canvas.graphics.endFill();
                }
                
                // 放射性渐变填充
                function drawRadialGradient(e:ComponentEvent):void
                {                
                        canvas.graphics.lineStyle(1, 0x000000);
                        var gradientBoxMatrix:Matrix = new Matrix();
                        gradientBoxMatrix.createGradientBox(50, 20, 0);
                        
                        // GradientType.RADIAL - 放射性渐变
                        canvas.graphics.beginGradientFill(GradientType.RADIAL, [0xFF0000, 0x0000FF], [1, 1], [0, 255], gradientBoxMatrix, SpreadMethod.REFLECT);
                        
                        canvas.graphics.drawCircle(200, 200, 30);
                        canvas.graphics.endFill();
                }
                
                // 清除图形
                function clearGraphics(e:ComponentEvent):void
                {        
                        // clear() - 清除 Graphics 上的图形，并重置线条样式和填充等设置
                        canvas.graphics.clear();
                }
        }
}
 
 
2、转换
在 UI 上放置 3 个 Silder
分别名为：sliderScaleX, sliderScaleY, sliderRotate
分别用于演示 X 轴方向上的缩放，Y 轴方向上的缩放，旋转
再放置 2 个 Button
分别名为：btnMatrix, btnClearMatrix
分别用于演示仿射矩阵在图形转换上的应用，还原为对象的初始仿射矩阵转换
Main.as
package    
{
        import flash.display.MovieClip;
        import fl.events.ComponentEvent;
        import fl.events.SliderEvent;
        import flash.display.Shape;
        import flash.geom.Matrix;
        import flash.display.GradientType;
        import flash.display.SpreadMethod;
        
        public class Main extends MovieClip
        {
                var originalMatrix:Matrix;
                
                public function Main():void
                {
                        sliderScaleX.addEventListener(SliderEvent.THUMB_DRAG, scaleXHandler);
                        sliderScaleY.addEventListener(SliderEvent.THUMB_DRAG, scaleYHandler);
                        sliderRotate.addEventListener(SliderEvent.THUMB_DRAG, rotateHandler);
                        btnMatrix.addEventListener(ComponentEvent.BUTTON_DOWN, matrixHandler);
                        btnClearMatrix.addEventListener(ComponentEvent.BUTTON_DOWN, clearMatrixHandler);
                        
                        // 保存 canvas 的初始仿射矩阵转换
                        originalMatrix = canvas.transform.matrix;
                }
                
                
                // 在 x 轴方向上做缩放
                function scaleXHandler(e:SliderEvent):void
                {
                        // scaleX - x轴方向上的缩放比例
                        canvas.scaleX = e.value;
                }
                
                // 在 y 轴方向上做缩放
                function scaleYHandler(e:SliderEvent):void
                {
                        // scaleY - y轴方向上的缩放比例
                        canvas.scaleY = e.value;
                }
                
                // 旋转
                function rotateHandler(e:SliderEvent):void
                {
                        // rotation - 旋转的度数
                        canvas.rotation = e.value;
                }
                
                
                // 仿射矩阵在图形转换上的应用
                function matrixHandler(e:ComponentEvent):void
                {
                        var matrix:Matrix = new Matrix();

                        // rotate() - 旋转的角度
                        matrix.rotate(10);
                        
                        // translate() - 平移的距离
                        matrix.translate(200, 200);
                        
                        // scale() - 缩放的比例
                        matrix.scale(1.2, 1.2);
                        
                        var skewMatrix:Matrix = new Matrix();
                        // 调整 b 属性将矩阵垂直倾斜
                        // 调整 c 属性将矩阵水平倾斜
                        skewMatrix.b = Math.tan(0.78);    
                        
                        // concat() - 组合两个仿射矩阵
                        matrix.concat(skewMatrix);

                        // 在对象上应用仿射矩阵转换
                        canvas.transform.matrix = matrix;
                }
                
                // 还原为初始的仿射矩阵转换
                function clearMatrixHandler(e:ComponentEvent):void
                {
                        // 设置 canvas 的仿射矩阵转换为初始的仿射矩阵
                        canvas.transform.matrix = originalMatrix;
                }
        }
}