java - 在 Canvas 上仅显示图像的特定部分

Question

我目前正在 Android Studio 的 Canvas 上绘制图像，如下所示:

public class Floor{
    int x;
    int y;
    int width;
    int height;
    Drawable image;

    public Floor(int x, int y, int width, int height, Context context) {
        this.x = x;
        this.y = y;
        this.height = height;
        this.width = width;
        this.image = this.context.getResources().getDrawable(R.drawable.floorimage);
    }

    // this method is called in the draw loop
    public void draw(Canvas canvas) {

        Rect imageBounds = new Rect(this.x, this.y, this.x + this.width, this.y + this.height);

        this.image.setBounds(imageBounds);
        this.image.draw(canvas);
    }
}

所以图片大小是根据宽高设置的。然而，我不想重置图像大小，我想绘制图像的一部分，包括在宽度和高度中。

可视化:

我知道这个线程: Android - Display part of a large image

但是该线程仅展示了如何解决我的 ImageView 问题。有没有人有在 Canvas 中执行此操作的解决方案？

Answer 1

在 Floor.draw() 中试试这个:

public void draw(Canvas canvas) {

 Rect canvasBounds = canvas.getClipBounds();         //get the current clip(Canvas drawing area)
 this.image.setBounds(canvasBounds);      //same bounds as canvas, so image is the same size. We clip next

 Rect imageBounds=new Rect(0,0,this.width,this.height); //You should move this line to constructor. You know, performance and all.                                                                

 canvas.save();                 //save the current clip. You can't use canvasBounds to restore it later, there is no setClipBounds()
 canvas.clipRect(imageBounds); //clip the canvas so you draw only the width and height u want
 this.image.draw(canvas);
 canvas.restore();       //restore the Canvas clip. 

 //do other drawings with full size canvas

编码愉快!