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Maintain aspect ratio of bitmap drawables set as windowBackground on Android
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| import android.graphics.Canvas; | |
| import android.graphics.ColorFilter; | |
| import android.graphics.Matrix; | |
| import android.graphics.Rect; | |
| import android.graphics.RectF; | |
| import android.graphics.drawable.Drawable; | |
| import android.support.annotation.IntRange; | |
| import android.support.annotation.NonNull; | |
| import android.support.annotation.Nullable; | |
| /** | |
| * Drawable decorator which draws the target drawable similarly to an ImageView with scaleType=centerCrop | |
| * | |
| * Example usage: | |
| * final Drawable bg = getResources().getDrawable(R.drawable.screen); | |
| * getWindow().setBackgroundDrawable(new CenterCropDrawable(bg)); | |
| */ | |
| public class CenterCropDrawable extends Drawable { | |
| @NonNull | |
| private final Drawable target; | |
| public CenterCropDrawable(@NonNull Drawable target) { | |
| this.target = target; | |
| } | |
| @Override | |
| public void setBounds(@NonNull Rect bounds) { | |
| super.setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); | |
| } | |
| @Override | |
| public void setBounds(int left, int top, int right, int bottom) { | |
| final RectF sourceRect = new RectF(0, 0, target.getIntrinsicWidth(), target.getIntrinsicHeight()); | |
| final RectF screenRect = new RectF(left, top, right, bottom); | |
| final Matrix matrix = new Matrix(); | |
| matrix.setRectToRect(screenRect, sourceRect, Matrix.ScaleToFit.CENTER); | |
| final Matrix inverse = new Matrix(); | |
| matrix.invert(inverse); | |
| inverse.mapRect(sourceRect); | |
| target.setBounds(Math.round(sourceRect.left), Math.round(sourceRect.top), | |
| Math.round(sourceRect.right), Math.round(sourceRect.bottom)); | |
| super.setBounds(left, top, right, bottom); | |
| } | |
| @Override | |
| public void draw(@NonNull Canvas canvas) { | |
| canvas.save(Canvas.ALL_SAVE_FLAG); | |
| canvas.clipRect(getBounds()); | |
| target.draw(canvas); | |
| canvas.restore(); | |
| } | |
| @Override | |
| public void setAlpha(@IntRange(from = 0, to = 255) int alpha) { | |
| target.setAlpha(alpha); | |
| } | |
| @Override | |
| public void setColorFilter(@Nullable ColorFilter colorFilter) { | |
| target.setColorFilter(colorFilter); | |
| } | |
| @Override | |
| public int getOpacity() { | |
| return target.getOpacity(); | |
| } | |
| } |
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