Android高级渲染Shader-BitmapShader

aruba

发布于 2020-07-03 10:52:17

8130

发布于 2020-07-03 10:52:17

文章被收录于专栏：android技术

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

    /**
     * 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

    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

    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

    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);
    }