h529820165的专栏

在创建新的控件或修改现有的控件时，我们都会涉及到重写控件或View的onDraw方法。 onDraw方法会传入一个Canvas对象，它是你用来绘制控件视觉界面的画布。 在onDraw方法里，我们经常会看到调用save和restore方法，它们到底是干什么用的呢？ ❑ save：用来保存Canvas的状态。save之后，可以调用Canvas的平移、放缩、旋转、错切、裁剪等操作...

//绘制矩形   canvas.drawRect(new Rect(150, 75, 260, 120), mPaint);   //设置裁剪区域   canvas.clipRect(10, 10, 280, 260);  以屏幕的左上角为原点left ： 矩形左边的X坐标   150        ---->图片中的A点 top:    矩形顶部的Y坐标...

public void getPixels (int[] pixels, int offset, int stride, int x, int y, int width, int height) Since: API Level 1 Returns in pixels[] a copy of the data in the bitmap. Each value is a ...

 Colors are represented as packed ints, made up of 4 bytes: alpha, red, green, blue  Each component ranges between 0..255 with 0 meaning no contribution for that component, and 255 meaning 100% co...