如何分别旋转帆布的不同部分在Android

Question

我有自定义视图，其中包含许多矩形和椭圆和.....我可以旋转我的整个画布（矩形和椭圆和....）通过使用canvas.rotate （度，cneterX，centerY）

但在我的视图的底部，我想有一个菜单，当我使用canvas.rotate（）不旋转的东西。这意味着我想旋转这些矩形和椭圆形，但不想旋转我的菜单，将使用相同的画布创建。

@Override 
    protected void onDraw(Canvas canvas) { 

    float ringWidth = textHeight + 4; 
    int height = getMeasuredHeight(); 
    int width =getMeasuredWidth(); 

    int px = width; 
    int py = height/2; 
    Point center = new Point(px,py); 

    int radius = Math.max(px, py)-2; 

    int UpperSide = center.y; 

    RectF boundingBox = new RectF(center.x - radius, center.y - radius, center.x + radius, center.y + radius); 

    RectF innerBoundingBox = new RectF(center.x - radius , center.y - radius , center.x + radius, center.y + radius); 


    RectF GroundSectionBox = new RectF(center.x - radius,UpperSide ,center.x + radius,center.y + radius); 

    RectF RightPanel = new RectF(center.x + width -(width/4), center.y - (radius/2)+10, center.x+radius- ringWidth, center.y + (radius/2)-10); 
    RectF LeftPanel = new RectF(center.x - radius + ringWidth ,center.y - (radius/2)+10, center.x - width + (width/4), center.y + (radius/2)-10); 

    RectF RightBlack = new RectF(center.x + width -(width/4),center.y-(radius/10),center.x+radius- ringWidth,center.y + (radius/10)); 
    RectF leftBlack = new RectF(center.x - radius + ringWidth ,center.y - (radius/10), center.x - width + (width/4), center.y + (radius/10)); 

     . 
     . 
    canvas.drawRect(innerBoundingBox, groundPaint); 

    canvas.drawPath(skyPath, skyPaint);  
    canvas.drawRect(GroundSectionBox, skyPaint); 

    canvas.drawPath(skyPath, markerPaint); 

    canvas.drawRect(RightBlack, sideBlack); 
    canvas.drawRect(leftBlack, sideBlack); 


    canvas.drawRect(RightPanel, RightPanelup); 
    canvas.drawRect(LeftPanel, LeftPanelUp); 
     . 
     . 
     } 

Answer 1

您可以使用Canvas上的保存和恢复方法在转换中绘制东西，然后恢复到原始状态。这里有一个例子：

protected void onDraw(Canvas canvas) 
{ 
    canvas.save(); // Canvas is in original state. Save it before anything 

    // Perform any transformations you want here (like rotate) 
    // Draw while your transformations are in place (like ovals) 

    canvas.restore(); // Canvas state returned to what it was when you called save 

    // Draw things that need to be drawn without any transformations 
} 

希望这有助于:)