我们在自定义控件的onDraw()方法中，使用Canvas的drawXX方法画各种形状，而画笔的Shader是用于图形的着色和外观，Shader即着色器
BitmapShader--位图图像渲染，用BitMap对绘制的图形进行渲染着色，简单来说就是用图片对图形进行贴图
代码语言：javascript复制 /**
* Call this to create a new shader that will draw with a bitmap.
*
* @param bitmap The bitmap to use inside the shader
* @param tileX The tiling mode for x to draw the bitmap in.
* @param tileY The tiling mode for y to draw the bitmap in.
*/
public BitmapShader(@NonNull Bitmap bitmap, @NonNull TileMode tileX, @NonNull TileMode tileY) {
this(bitmap, tileX.nativeInt, tileY.nativeInt);
}实例化BitmapShader需要三个参数
- Bitmap
- X轴的拉伸模式
- Y轴的拉伸模式
拉伸模式分为三种
- CLAMP --是拉伸最后一个像素铺满
- MIRROR ---是横向纵向不足处不断翻转镜像平铺
- REPEAT ---类似电脑壁纸，横向纵向不足的重复放置
CLAMP模式
代码语言：javascript复制 private void drawClampBitmapShader(Canvas canvas){
BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP,Shader.TileMode.CLAMP);
paint.setShader(bitmapShader);
RectF rect = new RectF(0,0,800,100);
canvas.drawRect(rect,paint);
}
CLAMP效果.jpg
MIRROR模式
代码语言：javascript复制 private void drawMirrorBitmapShader(Canvas canvas) {
BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.MIRROR,Shader.TileMode.MIRROR);
paint.setShader(bitmapShader);
RectF rect = new RectF(0,0,1000,1000);
canvas.drawRect(rect,paint);
}
MIRROR效果.jpg
REPEAT模式
代码语言：javascript复制 private void drawRepeatBitmapShader(Canvas canvas) {
BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.REPEAT,Shader.TileMode.REPEAT);
paint.setShader(bitmapShader);
RectF rect = new RectF(0,0,1000,1000);
canvas.drawRect(rect,paint);
}
REPEAT效果.jpg
