[英]How to draw a partial round rect on a android canvas?
我想在画布上绘制一个用颜色(或位图)填充并带有笔触的圆角矩形 ,但不带有某些选定的角,并且某些选定的侧面上也没有边框 。 任何想法,我怎么能做到这一点?
您可以将绘图过程分为两部分。
绘制填充区域
当尝试绘制标准sdk API不支持的形状时,Canvas.drawPath方法将是一种很好的方法。您可以定义四个变量来表示四个角的半径。
Path path = new Path(); Rect drawingRect = {the rect area you want to draw} RectF topLeftArcBound = new RectF(); RectF topRightArcBound = new RectF(); RectF bottomLeftArcBound = new RectF(); RectF bottomRightArcBound = new RectF(); topRightArcBound.set(drawingRect.right - topRightRadius * 2, drawingRect.top, drawingRect.right, drawingRect.top + topRightRadius * 2); bottomRightArcBound.set(drawingRect.right - bottomRightRadius * 2, drawingRect.bottom - bottomRightRadius * 2, drawingRect.right, drawingRect.bottom); bottomLeftArcBound.set(drawingRect.left, drawingRect.bottom - bottomLeftRadius * 2, drawingRect.left + bottomLeftRadius * 2, drawingRect.bottom); topLeftArcBound.set(drawingRect.left, drawingRect.top, drawingRect.left + topLeftRadius * 2, drawingRect.top + topLeftRadius * 2); path.reset(); path.moveTo(drawingRect.left + topLeftRadius, drawingRect.top); //draw top horizontal line path.lineTo(drawingRect.right - topRightRadius, drawingRect.top); //draw top-right corner path.arcTo(topRightArcBound, -90, 90); //draw right vertical line path.lineTo(drawingRect.right, drawingRect.bottom - bottomRightRadius); //draw bottom-right corner path.arcTo(bottomRightArcBound, 0, 90); //draw bottom horizontal line path.lineTo(drawingRect.left - bottomLeftRadius, drawingRect.bottom); //draw bottom-left corner path.arcTo(bottomLeftArcBound, 90, 90); //draw left vertical line path.lineTo(drawingRect.left, drawingRect.top + topLeftRadius); //draw top-left corner path.arcTo(topLeftArcBound, 180, 90); path.close(); paint.setStyle(Paint.Style.FILL); canvas.drawPath(path, paint);
您可以将所选角的半径设置为零
画边框
边框包含八个部分:
使用int值包含选定的部分将是一个好主意
\n 私有静态最终int TOP_LEFT_CORNER = 0x1;\n 私有静态最终int TOP_LINE = 0x2;\n 私有静态最终整数TOP_RIGHT_CORNER = 0x4;\n 私有静态最终int RIGHT_LINE = 0x8;\n 私有静态最终int BOTTOM_RIGHT_CORNER = 0x10;\n 私有静态最终int BOTTOM_LINE = 0x20;\n 私有静态最终int BOTTOM_LEFT_CORNER = 0x40;\n 私有静态最终int LEFT_LINE = 0x80;\n\n private int selectedParts = TOP_LEFT_CORNER | TOP_LINE | TOP_RIGHT_CORNER;\n
现在我们可以根据selectedParts绘制边框:
\n paint.setStyle(Paint.Style.STROKE);\n if((selectedParts和TOP_LINE)> 0){\n canvas.drawLine(drawingRect.left + topLeftRadius,drawingRect.top,drawingRect.right-topRightRadius,drawingRect.top);\n }\n\n if((selectedParts&TOP_RIGHT_CORNER)> 0){\n canvas.drawArc(topRightArcBound,-90,90,false,paint);\n }\n\n if((selectedParts&RIGHT_LINE)> 0){\n canvas.drawLine(drawingRect.right,drawingRect.top + topRightRadius,drawingRect.right,drawingRect.bottom-bottomRightRadius,paint);\n }\n\n if((selectedParts&BOTTOM_RIGHT_CORNER)> 0){\n canvas.drawArc(bottomRightArcBound,0,90,false,paint);\n }\n\n if((selectedParts&BOTTOM_LINE)> 0){\n canvas.drawLine(drawingRect.right-bottomRightRadius,drawingRect.bottom。drawingRect.left + bottomLeftRadius,drawingRect.bottom,paint);\n }\n\n if((selectedParts&BOTTOM_LEFT_CORNER)> 0){\n canvas.drawArc(bottomLeftArcBound,90,90,false,paint);\n }\n\n if((selectedParts&LEFT_LINE)> 0){\n canvas.drawLine(drawingRect.left,drawingRect.bottom-bottomLeftRadius,drawingRect.left,drawingRect.top + topLeftRadius,paint);\n }\n\n if((selectedParts&TOP_LEFT_CORNER)> 0){\n canvas.drawArc(topLeftArcBound,180,90,false,paint);\n }\n
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