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An Android library that provides an image cropping capabilities
/*
* Copyright (C) 2009 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.isapp.android.crop;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.widget.ImageView;
/*
* Modified from original in AOSP.
*/
abstract class ImageViewTouchBase extends ImageView {
private static final float SCALE_RATE = 1.25F;
// This is the base transformation which is used to show the image
// initially. The current computation for this shows the image in
// it's entirety, letterboxing as needed. One could choose to
// show the image as cropped instead.
//
// This matrix is recomputed when we go from the thumbnail image to
// the full size image.
protected Matrix baseMatrix = new Matrix();
// This is the supplementary transformation which reflects what
// the user has done in terms of zooming and panning.
//
// This matrix remains the same when we go from the thumbnail image
// to the full size image.
protected Matrix suppMatrix = new Matrix();
// This is the final matrix which is computed as the concatentation
// of the base matrix and the supplementary matrix.
private final Matrix displayMatrix = new Matrix();
// Temporary buffer used for getting the values out of a matrix.
private final float[] matrixValues = new float[9];
// The current bitmap being displayed.
protected final RotateBitmap bitmapDisplayed = new RotateBitmap(null, 0);
int thisWidth = -1;
int thisHeight = -1;
float maxZoom;
private Runnable onLayoutRunnable;
protected Handler handler = new Handler();
// ImageViewTouchBase will pass a Bitmap to the Recycler if it has finished
// its use of that Bitmap
public interface Recycler {
public void recycle(Bitmap b);
}
private Recycler recycler;
public ImageViewTouchBase(Context context) {
super(context);
init();
}
public ImageViewTouchBase(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public ImageViewTouchBase(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
void setRecycler(Recycler recycler) {
this.recycler = recycler;
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
thisWidth = right - left;
thisHeight = bottom - top;
Runnable r = onLayoutRunnable;
if (r != null) {
onLayoutRunnable = null;
r.run();
}
if (bitmapDisplayed.getBitmap() != null) {
getProperBaseMatrix(bitmapDisplayed, baseMatrix, true);
setImageMatrix(getImageViewMatrix());
}
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
event.startTracking();
return true;
}
return super.onKeyDown(keyCode, event);
}
@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && event.isTracking() && !event.isCanceled()) {
if (getScale() > 1.0f) {
// If we're zoomed in, pressing Back jumps out to show the
// entire image, otherwise Back returns the user to the gallery
zoomTo(1.0f);
return true;
}
}
return super.onKeyUp(keyCode, event);
}
@Override
public void setImageBitmap(Bitmap bitmap) {
setImageBitmap(bitmap, 0);
}
private void setImageBitmap(Bitmap bitmap, int rotation) {
super.setImageBitmap(bitmap);
Drawable d = getDrawable();
if (d != null) {
d.setDither(true);
}
Bitmap old = bitmapDisplayed.getBitmap();
bitmapDisplayed.setBitmap(bitmap);
bitmapDisplayed.setRotation(rotation);
if (old != null && old != bitmap && recycler != null) {
recycler.recycle(old);
}
}
void clear() {
setImageBitmapResetBase(null, true);
}
// This function changes bitmap, reset base matrix according to the size
// of the bitmap, and optionally reset the supplementary matrix
void setImageBitmapResetBase(final Bitmap bitmap, final boolean resetSupp) {
setImageRotateBitmapResetBase(new RotateBitmap(bitmap, 0), resetSupp);
}
void setImageRotateBitmapResetBase(final RotateBitmap bitmap, final boolean resetSupp) {
final int viewWidth = getWidth();
if (viewWidth <= 0) {
onLayoutRunnable = new Runnable() {
public void run() {
setImageRotateBitmapResetBase(bitmap, resetSupp);
}
};
return;
}
if (bitmap.getBitmap() != null) {
getProperBaseMatrix(bitmap, baseMatrix, true);
setImageBitmap(bitmap.getBitmap(), bitmap.getRotation());
} else {
baseMatrix.reset();
setImageBitmap(null);
}
if (resetSupp) {
suppMatrix.reset();
}
setImageMatrix(getImageViewMatrix());
maxZoom = calculateMaxZoom();
}
// Center as much as possible in one or both axis. Centering is
// defined as follows: if the image is scaled down below the
// view's dimensions then center it (literally). If the image
// is scaled larger than the view and is translated out of view
// then translate it back into view (i.e. eliminate black bars).
protected void center(boolean horizontal, boolean vertical) {
final Bitmap bitmap = bitmapDisplayed.getBitmap();
if (bitmap == null) {
return;
}
Matrix m = getImageViewMatrix();
RectF rect = new RectF(0, 0, bitmap.getWidth(), bitmap.getHeight());
m.mapRect(rect);
float height = rect.height();
float width = rect.width();
float deltaX = 0, deltaY = 0;
if (vertical) {
int viewHeight = getHeight();
if (height < viewHeight) {
deltaY = (viewHeight - height) / 2 - rect.top;
} else if (rect.top > 0) {
deltaY = -rect.top;
} else if (rect.bottom < viewHeight) {
deltaY = getHeight() - rect.bottom;
}
}
if (horizontal) {
int viewWidth = getWidth();
if (width < viewWidth) {
deltaX = (viewWidth - width) / 2 - rect.left;
} else if (rect.left > 0) {
deltaX = -rect.left;
} else if (rect.right < viewWidth) {
deltaX = viewWidth - rect.right;
}
}
postTranslate(deltaX, deltaY);
setImageMatrix(getImageViewMatrix());
}
private void init() {
setScaleType(ImageView.ScaleType.MATRIX);
}
protected float getValue(Matrix matrix, int whichValue) {
matrix.getValues(matrixValues);
return matrixValues[whichValue];
}
// Get the scale factor out of the matrix.
protected float getScale(Matrix matrix) {
return getValue(matrix, Matrix.MSCALE_X);
}
protected float getScale() {
return getScale(suppMatrix);
}
// Setup the base matrix so that the image is centered and scaled properly.
private void getProperBaseMatrix(RotateBitmap bitmap, Matrix matrix, boolean includeRotation) {
float viewWidth = getWidth();
float viewHeight = getHeight();
float w = bitmap.getWidth();
float h = bitmap.getHeight();
matrix.reset();
// We limit up-scaling to 3x otherwise the result may look bad if it's a small icon
float widthScale = Math.min(viewWidth / w, 3.0f);
float heightScale = Math.min(viewHeight / h, 3.0f);
float scale = Math.min(widthScale, heightScale);
if (includeRotation) {
matrix.postConcat(bitmap.getRotateMatrix());
}
matrix.postScale(scale, scale);
matrix.postTranslate((viewWidth - w * scale) / 2F, (viewHeight - h * scale) / 2F);
}
// Combine the base matrix and the supp matrix to make the final matrix
protected Matrix getImageViewMatrix() {
// The final matrix is computed as the concatentation of the base matrix
// and the supplementary matrix
displayMatrix.set(baseMatrix);
displayMatrix.postConcat(suppMatrix);
return displayMatrix;
}
public Matrix getUnrotatedMatrix(){
Matrix unrotated = new Matrix();
getProperBaseMatrix(bitmapDisplayed, unrotated, false);
unrotated.postConcat(suppMatrix);
return unrotated;
}
protected float calculateMaxZoom() {
if (bitmapDisplayed.getBitmap() == null) {
return 1F;
}
float fw = (float) bitmapDisplayed.getWidth() / (float) thisWidth;
float fh = (float) bitmapDisplayed.getHeight() / (float) thisHeight;
return Math.max(fw, fh) * 4; // 400%
}
protected void zoomTo(float scale, float centerX, float centerY) {
if (scale > maxZoom) {
scale = maxZoom;
}
float oldScale = getScale();
float deltaScale = scale / oldScale;
suppMatrix.postScale(deltaScale, deltaScale, centerX, centerY);
setImageMatrix(getImageViewMatrix());
center(true, true);
}
protected void zoomTo(final float scale, final float centerX,
final float centerY, final float durationMs) {
final float incrementPerMs = (scale - getScale()) / durationMs;
final float oldScale = getScale();
final long startTime = System.currentTimeMillis();
handler.post(new Runnable() {
public void run() {
long now = System.currentTimeMillis();
float currentMs = Math.min(durationMs, now - startTime);
float target = oldScale + (incrementPerMs * currentMs);
zoomTo(target, centerX, centerY);
if (currentMs < durationMs) {
handler.post(this);
}
}
});
}
protected void zoomTo(float scale) {
float cx = getWidth() / 2F;
float cy = getHeight() / 2F;
zoomTo(scale, cx, cy);
}
protected void zoomIn() {
zoomIn(SCALE_RATE);
}
protected void zoomOut() {
zoomOut(SCALE_RATE);
}
protected void zoomIn(float rate) {
if (getScale() >= maxZoom) {
return; // Don't let the user zoom into the molecular level
}
if (bitmapDisplayed.getBitmap() == null) {
return;
}
float cx = getWidth() / 2F;
float cy = getHeight() / 2F;
suppMatrix.postScale(rate, rate, cx, cy);
setImageMatrix(getImageViewMatrix());
}
protected void zoomOut(float rate) {
if (bitmapDisplayed.getBitmap() == null) {
return;
}
float cx = getWidth() / 2F;
float cy = getHeight() / 2F;
// Zoom out to at most 1x
Matrix tmp = new Matrix(suppMatrix);
tmp.postScale(1F / rate, 1F / rate, cx, cy);
if (getScale(tmp) < 1F) {
suppMatrix.setScale(1F, 1F, cx, cy);
} else {
suppMatrix.postScale(1F / rate, 1F / rate, cx, cy);
}
setImageMatrix(getImageViewMatrix());
center(true, true);
}
protected void postTranslate(float dx, float dy) {
suppMatrix.postTranslate(dx, dy);
}
protected void panBy(float dx, float dy) {
postTranslate(dx, dy);
setImageMatrix(getImageViewMatrix());
}
}