android 在缩放和平移后从扩展图像视图中获取实际图像坐标

Question

在用户在图像上的 canvas 上绘制矩形后，我正在尝试检索图像的真实坐标。为此，我使用了 LayerDrawable，将位图图像作为底层。不幸的是，我的解决方案仅在比例因子为 1（未执行缩放）时有效。如果用户使用当前解决方案稍微缩放和平移，我会接近坐标，但有些不对劲并且它们不准确。因为我无法 post 此处的全部代码，所以我已将其上传到 pastebin (link). I also do a little bit of preprocessing and scale the image exactly so it fits the available size of my extended ImageView. For that i use a ViewTreeObserver and on the predraw method I find out exactly how much space i have available and scale the image to that size, so it fits the bigger dimension and the aspect ratio is kept. The code for it is here (link)。

最重要的部分是：

private void fixCoordinates(){
    //get utmost left,right,top,bottom corners from both begin and end coordinate
    float left = Math.min(beginCoordinate.x, endCoordinate.x);
    float top = Math.min(beginCoordinate.y, endCoordinate.y);
    float right = Math.max(beginCoordinate.x, endCoordinate.x);
    float bottom = Math.max(beginCoordinate.y, endCoordinate.y);
    //reassign them to proper begin and end
    PointF b = new PointF(left,top);
    PointF e = new PointF(right,bottom);

    //m[5] and m[2] denote offsets (empty spaces) when they are positive
    if(m[2] > 0){

        b.x = b.x - m[2];
        e.x = e.x - m[2];
    }
    if(m[5] > 0){

        b.y = b.y - m[5];
        e.y = e.y - m[5];
    }

    //safety
    if(b.x < 0){
        b.x = 0;
    }
    if(b.y < 0){
        b.y = 0;
    }
    if(e.x > layers[0].getIntrinsicWidth()){
        e.x = layers[0].getIntrinsicWidth();
    }
    if(e.y > layers[0].getIntrinsicHeight()){
        e.y = layers[0].getIntrinsicHeight();
    }
    //we only have one scale factor, because in the preprocessing we rescale and fit the image
    setBeginCoordinate(b);
    setEndCoordinate(e);
}

在 MotionEvent 之后，我使用此函数将开始坐标设置为最大顶部和左侧，将结束坐标设置为底部和右侧。

到原始图像的实际映射在这里完成：

private PointF mapBeginCoordinates(PointF beginCoordinate, PointF endCoordinate){
    float left = Math.min(beginCoordinate.x, endCoordinate.x);
    float top = Math.min(beginCoordinate.y, endCoordinate.y);

    double wAr = UtilFunctions.getAspectRatio(getOriginalWidth(), layers[0].getIntrinsicWidth());
    double hAr = UtilFunctions.getAspectRatio(getOriginalHeight(), layers[0].getIntrinsicHeight());
    left = (float)((double)left/wAr);
    top = (float)((double)top/hAr);

    float[] imageMatrix = new float[9];
    getImageMatrix().getValues(imageMatrix);
    float scaleFactorX = imageMatrix[Matrix.MSCALE_X];
    float scaleFactorY = imageMatrix[Matrix.MSCALE_Y];

    float fixedTransX = 1;
    float fixedTransY = 1;


    //m[5] height m[2] width
    if(m[2] < 0){
        fixedTransX = (m[2]*scaleFactorX);
    }
    if(m[5] < 0){
        fixedTransY = (m[5]*scaleFactorY);
    }

    left = left/scaleFactorX + Math.abs(fixedTransX);
    top = top/scaleFactorY + Math.abs(fixedTransY);

    return new PointF(left,top);
}

结束坐标的代码相同。 pastebin 中的代码有点乱，因为我已经尝试了 2 天的许多不同的东西来让它工作，但有些东西让我望而却步。我将不胜感激任何帮助。

Answer 1

我设法通过使用 Mike Ortiz TouchImageView

解决了我的问题

我用来将坐标映射到原始位图的代码是这样的：

private PointF mapBeginCoordinates(PointF beginCoordinate, PointF endCoordinate) {
    //TODO we only have one aspect ratio for the current picture, so we should remove redundancy
    float left = Math.min(beginCoordinate.x, endCoordinate.x);
    float top = Math.min(beginCoordinate.y, endCoordinate.y);
    double wAr = UtilFunctions.getAspectRatio(originalWidth, layers[0].getIntrinsicWidth());
    double hAr = UtilFunctions.getAspectRatio(originalHeight, layers[0].getIntrinsicHeight());
    if(!isZoomed()) {
        left = (float) (left / wAr);
        top = (float) (top / hAr);
    }
    if(isZoomed()) {
        PointF b = transformCoordTouchToBitmap(left,top,true);
        left = (float) (b.x / wAr);
        top = (float) (b.y / hAr);
    }
    return new PointF(left,top);
}

我仍然使用上面的 fixcoordinates 代码来准备我的 left/top - right/bottom 位置。感谢您的回答

android 在缩放和平移后从扩展图像视图中获取实际图像坐标

android get actual image coordinates from an extended imageview after zoom and pan

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