画像を四角形に変形することができない場合があります。

Question

matrix.setPolyToPoly関数を使用して、ビットマップの選択された領域（四隅）を矩形に変換します。しかし、次の例では：

polyToPoly機能は、視点変換失敗：

私はテストのための2つのラインを描いた、私が選択した4つのポイントを配置したい場所を、行がマークします。

私は間違っていますか？ありがとう！

EDIT：私はcanvas.drawBitmapMeshを使用して問題を解決しました。ありがとうございました。pskinkあなたのアドバイスのために！

これは、おかげであなたがsetPolyToPoly` `ですべてを行うことはできません最終的なコード

private float[] generateVertices(int widthBitmap, int heightBitmap) { 
    float[] vertices=new float[(WIDTH_BLOCK+1)*(HEIGHT_BLOCK+1)*2]; 

    float widthBlock = (float)widthBitmap/WIDTH_BLOCK; 
    float heightBlock = (float)heightBitmap/HEIGHT_BLOCK; 

    for(int i=0;i<=HEIGHT_BLOCK;i++) 
     for(int j=0;j<=WIDTH_BLOCK;j++) { 
      vertices[i * ((HEIGHT_BLOCK+1)*2) + (j*2)] = j * widthBlock; 
      vertices[i * ((HEIGHT_BLOCK+1)*2) + (j*2)+1] = i * heightBlock; 
     } 
    return vertices; 
} 

private Bitmap perspectiveTransformation(Bitmap bitmap, ArrayList<Point> bitmapPoints) { 

    Bitmap correctedBitmap; 
    int maxX = (int) Math.max(Math.abs(bitmapPoints.get(0).x - bitmapPoints.get(1).x), Math.abs(bitmapPoints.get(2).x - bitmapPoints.get(3).x)); 
    int maxY = (int) Math.max(Math.abs(bitmapPoints.get(0).y - bitmapPoints.get(3).y), Math.abs(bitmapPoints.get(1).y - bitmapPoints.get(2).y)); 
    Log.d("max", "x=" + maxX + " y=" + maxY); //This is the desired final size 

    Bitmap.Config conf = Bitmap.Config.ARGB_8888; 
    correctedBitmap = Bitmap.createBitmap(maxX,maxY,conf); //the final bitmap 
    float mVertices[] =generateVertices(bitmap.getWidth(),bitmap.getHeight()); 

    Point mLeftTop = bitmapPoints.get(0); 
    Point mRightTop = bitmapPoints.get(1); 
    Point mLeftBot = bitmapPoints.get(3); 
    Point mRightBot = bitmapPoints.get(2); //the points on the image where the user has clicked 

    Canvas canvas = new Canvas(correctedBitmap); 

    Matrix matrix = new Matrix(); 
    matrix.setPolyToPoly(
      new float[]{mLeftTop.x, mLeftTop.y, 
        mRightTop.x, mRightTop.y, 
        mRightBot.x, mRightBot.y, 
        mLeftBot.x, mLeftBot.y //the user's points 
      }, 
      0, 
      new float[]{0, 0, 
        maxX - 1, 0, 
        maxX - 1, maxY - 1, 
        0, maxY - 1    //where I want the user points in the corrected image 
      } 
      , 0, 4); 

    canvas.concat(matrix); 

    Paint paint = new Paint(); 
    paint.setAntiAlias(true);  //testing parameters 
    paint.setFilterBitmap(true); //testing parameters 

    paint.setColor(Color.BLUE); 
    paint.setStyle(Paint.Style.STROKE); 

    canvas.drawBitmapMesh(bitmap, WIDTH_BLOCK , HEIGHT_BLOCK, mVertices,0,null,0, paint); //draw the original bitmap into the corrected bitmap with PolyToPoly transformation matrix 

    canvas.drawLine(mLeftTop.x, mLeftTop.y, mRightBot.x, mRightBot.y, paint); //draw two lines for testing the transformation matrix 
    canvas.drawLine(mLeftBot.x, mLeftBot.y, mRightTop.x, mRightTop.y, paint); 

    //bitmap.recycle(); //just testing 

    return correctedBitmap; 
} 

Answer 1

private float[] generateVertices(int widthBitmap, int heightBitmap) { 
    float[] vertices=new float[(WIDTH_BLOCK+1)*(HEIGHT_BLOCK+1)*2]; 

    float widthBlock = (float)widthBitmap/WIDTH_BLOCK; 
    float heightBlock = (float)heightBitmap/HEIGHT_BLOCK; 

    for(int i=0;i<=HEIGHT_BLOCK;i++) 
     for(int j=0;j<=WIDTH_BLOCK;j++) { 
      vertices[i * ((HEIGHT_BLOCK+1)*2) + (j*2)] = j * widthBlock; 
      vertices[i * ((HEIGHT_BLOCK+1)*2) + (j*2)+1] = i * heightBlock; 
     } 
    return vertices; 
} 

private Bitmap perspectiveTransformation(Bitmap bitmap, ArrayList<Point> bitmapPoints) { 

    Bitmap correctedBitmap; 
    int maxX = (int) Math.max(Math.abs(bitmapPoints.get(0).x - bitmapPoints.get(1).x), Math.abs(bitmapPoints.get(2).x - bitmapPoints.get(3).x)); 
    int maxY = (int) Math.max(Math.abs(bitmapPoints.get(0).y - bitmapPoints.get(3).y), Math.abs(bitmapPoints.get(1).y - bitmapPoints.get(2).y)); 
    Log.d("max", "x=" + maxX + " y=" + maxY); //This is the desired final size 

    Bitmap.Config conf = Bitmap.Config.ARGB_8888; 
    correctedBitmap = Bitmap.createBitmap(maxX,maxY,conf); //the final bitmap 
    float mVertices[] =generateVertices(bitmap.getWidth(),bitmap.getHeight()); 

    Point mLeftTop = bitmapPoints.get(0); 
    Point mRightTop = bitmapPoints.get(1); 
    Point mLeftBot = bitmapPoints.get(3); 
    Point mRightBot = bitmapPoints.get(2); //the points on the image where the user has clicked 

    Canvas canvas = new Canvas(correctedBitmap); 

    Matrix matrix = new Matrix(); 
    matrix.setPolyToPoly(
      new float[]{mLeftTop.x, mLeftTop.y, 
        mRightTop.x, mRightTop.y, 
        mRightBot.x, mRightBot.y, 
        mLeftBot.x, mLeftBot.y //the user's points 
      }, 
      0, 
      new float[]{0, 0, 
        maxX - 1, 0, 
        maxX - 1, maxY - 1, 
        0, maxY - 1    //where I want the user points in the corrected image 
      } 
      , 0, 4); 

    canvas.concat(matrix); 

    Paint paint = new Paint(); 
    paint.setAntiAlias(true);  //testing parameters 
    paint.setFilterBitmap(true); //testing parameters 

    paint.setColor(Color.BLUE); 
    paint.setStyle(Paint.Style.STROKE); 

    canvas.drawBitmapMesh(bitmap, WIDTH_BLOCK , HEIGHT_BLOCK, mVertices,0,null,0, paint); //draw the original bitmap into the corrected bitmap with PolyToPoly transformation matrix 

    canvas.drawLine(mLeftTop.x, mLeftTop.y, mRightBot.x, mRightBot.y, paint); //draw two lines for testing the transformation matrix 
    canvas.drawLine(mLeftBot.x, mLeftBot.y, mRightTop.x, mRightTop.y, paint); 

    //bitmap.recycle(); //just testing 

    return correctedBitmap; 
}