The task is to crop video by given points(like rectangle) and display the cropped video.
The code works with cropping the first halh of video(0, 0, videoWidth/2, videoHeight). But when i tryed to display the second one(videoWidth/2, 0, videoWidth, videoHeight), that is what was displayed.
The video is displayed on TextureView inside FrameLayout.
The part, that doesn't work:
private void updateTextureViewSize(int ax, int ay, int bx, int by) {
float scaleX;
float scaleY;
//proportions between screen and frame dimensions
scaleX = mVideoWidth / mDisplayWidth;
scaleY = mVideoHeight / mDisplayHeight;
float scaleRegionW = mVideoWidth / Math.abs(ax - bx);
float scaleRegionH = mVideoHeight / Math.abs(ay - by);
float scaleRegion = scaleRegionW < scaleRegionH ? scaleRegionW : scaleRegionH;
Matrix matrix = new Matrix();
if (scaleX > scaleY) {
matrix.setScale(scaleRegion / scaleY, scaleRegion);
matrix.postTranslate(-ax * (int) scaleRegion / scaleY, -ay * scaleRegion / scaleY);
} else {
matrix.setScale(scaleRegion, scaleRegion / scaleX);
matrix.postTranslate(-ax * scaleRegion / scaleX, -ay * scaleRegion / scaleX);
}
mTextureView.setTransform(matrix);
mTextureView.setLayoutParams(new FrameLayout.LayoutParams((int) mDisplayWidth, (int) mDisplayHeight));
}
The answer was found by Dmitry Yacenko. The full code.
An easy way to crop video by given points (ax, ay, bx, xy) is:
float scaleX = mDisplayWidth / mVideoWidth, scaleY = mDisplayHeight / mVideoHeight;
//proportions between screen and frame dimensions
float scale = mDisplayHeight / Math.abs(by - ay);
Matrix matrix = new Matrix();
matrix.reset();
matrix.setScale(scale / scaleX, scale / scaleY);
//scaling video
matrix.postTranslate(-scale * ax, -scale * ay);
//move video, so the needed part of it will be displayed properly
mTextureView.setLayoutParams(new FrameLayout.LayoutParams((int) mDisplayWidth, (int) mDisplayHeight));
mTextureView.setTransform(matrix);
//updating the Texture view