Question

我像疯子一样努力工作了超过我不愿承认的时间，并且多次放弃了我的尝试。这是我所拥有的最原始的版本，但是有两个问题：

1。）它只会缩放到图像的左上角，而没有其他位置。我希望用户可以缩放到他们想要的位置。

2。）我希望能够为用户平移图像，但是屏幕边缘使我受阻。可以这么说，我不确定如何保持这种状态滚动。

我看了看android.graphics.camera，还玩了android矩阵类，但是没法玩。我认为这可能是因为绘图循环部分使我的逻辑意识有些偏离，因为我通常不使用这些逻辑。

在绘制循环内调用的方法：

public void drawFrame(Canvas canvas) {
    //super.onDraw(canvas);
    int newWidth=0;
    int newHeight=0;
    float scale = gestures.getScaleFactor();
    if(this.mBackgroundBitmap!=null) {
        canvas.save();
        float screenScaleX = (float) (this.mBackgroundBitmap.getWidth() / (float) getWidth()) * scale;
        float screenScaleY = (float) (this.mBackgroundBitmap.getHeight() / (float) getHeight()) * scale;

        canvas.translate(gestures.getScaleFocusX()/2, gestures.getScaleFocusY()/2);

        newWidth = Math.round(this.mBackgroundBitmap.getWidth() / screenScaleX);
        newHeight = Math.round(this.mBackgroundBitmap.getHeight() / screenScaleY);
        scaledBitmap = Bitmap.createScaledBitmap(this.mBackgroundBitmap, newWidth, newHeight, true);
        canvas.drawBitmap(scaledBitmap,0,0, new Paint());
        canvas.restore();

    }

我在自定义Surfaceview中使用的手势类：

public class MaelstromGestures implements View.OnTouchListener, ScaleGestureDetector.OnScaleGestureListener, View.OnLongClickListener {
private View view;
private ScaleGestureDetector gestureScale;
public MapActivity mapActivity;

public float getScaleFactor() {
    return scaleFactor;
}

public void setScaleFactor(float scaleFactor) {
    this.scaleFactor = scaleFactor;
}

private float scaleFactor = 1;

public boolean isInScale() {
    return inScale;
}

boolean inScale=false;

private float scaleFocusX = 0;
private float scaleFocusY = 0;

public float getScaleFocusX(){
    return gestureScale.getFocusX();
}
public float getScaleFocusY(){
    return gestureScale.getFocusY();
}



public MaelstromGestures (Context c){ gestureScale = new ScaleGestureDetector(c, this); }

@Override
public boolean onTouch(View view, MotionEvent event) {
    this.view = view;
    gestureScale.onTouchEvent(event);
    mapActivity.doTouch(view,event);

    return true;
}



@Override
public boolean onScale(ScaleGestureDetector detector) {
    scaleFactor *= detector.getScaleFactor();
    //scaleFactor = (scaleFactor < 0.5f ? 0.5f : scaleFactor); // prevent our view from becoming too small //
    scaleFactor = Math.max(1.0f, Math.min(scaleFactor, 3.0f));//((float)((int)(scaleFactor * 25))) / 25; // Change precision to help with jitter when user just rests their fingers //

    //view.setScaleX(scaleFactor);
    //view.setScaleY(scaleFactor);
    return true;
}

@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
    inScale = true;
    scaleFocusX = gestureScale.getFocusX();
    scaleFocusY = gestureScale.getFocusY();
    return true;
}

@Override
public void onScaleEnd(ScaleGestureDetector detector) { inScale = false; }

}

在绘制循环内在Surfaceview的画布上缩放（缩放）为背景位图的一部分的正确方法

0 个答案: