/*******************************************************************************
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* Copyright 2013-2014 Sergey Tarasevich
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*******************************************************************************/
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package com.nostra13.universalimageloader.utils;
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import android.graphics.BitmapFactory;
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import android.opengl.GLES10;
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import com.nostra13.universalimageloader.core.assist.ImageSize;
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import com.nostra13.universalimageloader.core.assist.ViewScaleType;
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import com.nostra13.universalimageloader.core.imageaware.ImageAware;
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import javax.microedition.khronos.opengles.GL10;
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/**
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* Provides calculations with image sizes, scales
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*
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* @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
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* @since 1.8.3
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*/
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public final class ImageSizeUtils {
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private static final int DEFAULT_MAX_BITMAP_DIMENSION = 2048;
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private static ImageSize maxBitmapSize;
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static {
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int[] maxTextureSize = new int[1];
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GLES10.glGetIntegerv(GL10.GL_MAX_TEXTURE_SIZE, maxTextureSize, 0);
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int maxBitmapDimension = Math.max(maxTextureSize[0], DEFAULT_MAX_BITMAP_DIMENSION);
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maxBitmapSize = new ImageSize(maxBitmapDimension, maxBitmapDimension);
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}
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private ImageSizeUtils() {
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}
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/**
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* Defines target size for image aware view. Size is defined by target
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* {@link com.nostra13.universalimageloader.core.imageaware.ImageAware view} parameters, configuration
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* parameters or device display dimensions.<br />
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*/
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public static ImageSize defineTargetSizeForView(ImageAware imageAware, ImageSize maxImageSize) {
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int width = imageAware.getWidth();
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if (width <= 0) width = maxImageSize.getWidth();
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int height = imageAware.getHeight();
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if (height <= 0) height = maxImageSize.getHeight();
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return new ImageSize(width, height);
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}
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/**
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* Computes sample size for downscaling image size (<b>srcSize</b>) to view size (<b>targetSize</b>). This sample
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* size is used during
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* {@linkplain BitmapFactory#decodeStream(java.io.InputStream, android.graphics.Rect, android.graphics.BitmapFactory.Options)
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* decoding image} to bitmap.<br />
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* <br />
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* <b>Examples:</b><br />
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* <p/>
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* <pre>
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* srcSize(100x100), targetSize(10x10), powerOf2Scale = true -> sampleSize = 8
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* srcSize(100x100), targetSize(10x10), powerOf2Scale = false -> sampleSize = 10
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*
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* srcSize(100x100), targetSize(20x40), viewScaleType = FIT_INSIDE -> sampleSize = 5
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* srcSize(100x100), targetSize(20x40), viewScaleType = CROP -> sampleSize = 2
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* </pre>
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* <p/>
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* <br />
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* The sample size is the number of pixels in either dimension that correspond to a single pixel in the decoded
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* bitmap. For example, inSampleSize == 4 returns an image that is 1/4 the width/height of the original, and 1/16
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* the number of pixels. Any value <= 1 is treated the same as 1.
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*
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* @param srcSize Original (image) size
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* @param targetSize Target (view) size
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* @param viewScaleType {@linkplain ViewScaleType Scale type} for placing image in view
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* @param powerOf2Scale <i>true</i> - if sample size be a power of 2 (1, 2, 4, 8, ...)
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* @return Computed sample size
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*/
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public static int computeImageSampleSize(ImageSize srcSize, ImageSize targetSize, ViewScaleType viewScaleType,
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boolean powerOf2Scale) {
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final int srcWidth = srcSize.getWidth();
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final int srcHeight = srcSize.getHeight();
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final int targetWidth = targetSize.getWidth();
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final int targetHeight = targetSize.getHeight();
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int scale = 1;
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switch (viewScaleType) {
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case FIT_INSIDE:
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if (powerOf2Scale) {
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final int halfWidth = srcWidth / 2;
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final int halfHeight = srcHeight / 2;
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while ((halfWidth / scale) > targetWidth || (halfHeight / scale) > targetHeight) { // ||
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scale *= 2;
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}
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} else {
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scale = Math.max(srcWidth / targetWidth, srcHeight / targetHeight); // max
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}
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break;
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case CROP:
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if (powerOf2Scale) {
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final int halfWidth = srcWidth / 2;
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final int halfHeight = srcHeight / 2;
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while ((halfWidth / scale) > targetWidth && (halfHeight / scale) > targetHeight) { // &&
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scale *= 2;
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}
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} else {
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scale = Math.min(srcWidth / targetWidth, srcHeight / targetHeight); // min
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}
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break;
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}
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if (scale < 1) {
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scale = 1;
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}
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scale = considerMaxTextureSize(srcWidth, srcHeight, scale, powerOf2Scale);
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return scale;
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}
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private static int considerMaxTextureSize(int srcWidth, int srcHeight, int scale, boolean powerOf2) {
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final int maxWidth = maxBitmapSize.getWidth();
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final int maxHeight = maxBitmapSize.getHeight();
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while ((srcWidth / scale) > maxWidth || (srcHeight / scale) > maxHeight) {
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if (powerOf2) {
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scale *= 2;
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} else {
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scale++;
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}
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}
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return scale;
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}
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/**
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* Computes minimal sample size for downscaling image so result image size won't exceed max acceptable OpenGL
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* texture size.<br />
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* We can't create Bitmap in memory with size exceed max texture size (usually this is 2048x2048) so this method
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* calculate minimal sample size which should be applied to image to fit into these limits.
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*
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* @param srcSize Original image size
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* @return Minimal sample size
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*/
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public static int computeMinImageSampleSize(ImageSize srcSize) {
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final int srcWidth = srcSize.getWidth();
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final int srcHeight = srcSize.getHeight();
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final int targetWidth = maxBitmapSize.getWidth();
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final int targetHeight = maxBitmapSize.getHeight();
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final int widthScale = (int) Math.ceil((float) srcWidth / targetWidth);
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final int heightScale = (int) Math.ceil((float) srcHeight / targetHeight);
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return Math.max(widthScale, heightScale); // max
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}
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/**
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* Computes scale of target size (<b>targetSize</b>) to source size (<b>srcSize</b>).<br />
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* <br />
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* <b>Examples:</b><br />
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* <p/>
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* <pre>
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* srcSize(40x40), targetSize(10x10) -> scale = 0.25
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*
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* srcSize(10x10), targetSize(20x20), stretch = false -> scale = 1
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* srcSize(10x10), targetSize(20x20), stretch = true -> scale = 2
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*
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* srcSize(100x100), targetSize(20x40), viewScaleType = FIT_INSIDE -> scale = 0.2
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* srcSize(100x100), targetSize(20x40), viewScaleType = CROP -> scale = 0.4
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* </pre>
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*
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* @param srcSize Source (image) size
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* @param targetSize Target (view) size
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* @param viewScaleType {@linkplain ViewScaleType Scale type} for placing image in view
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* @param stretch Whether source size should be stretched if target size is larger than source size. If <b>false</b>
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* then result scale value can't be greater than 1.
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* @return Computed scale
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*/
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public static float computeImageScale(ImageSize srcSize, ImageSize targetSize, ViewScaleType viewScaleType,
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boolean stretch) {
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final int srcWidth = srcSize.getWidth();
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final int srcHeight = srcSize.getHeight();
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final int targetWidth = targetSize.getWidth();
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final int targetHeight = targetSize.getHeight();
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final float widthScale = (float) srcWidth / targetWidth;
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final float heightScale = (float) srcHeight / targetHeight;
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final int destWidth;
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final int destHeight;
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if ((viewScaleType == ViewScaleType.FIT_INSIDE && widthScale >= heightScale) || (viewScaleType == ViewScaleType.CROP && widthScale < heightScale)) {
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destWidth = targetWidth;
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destHeight = (int) (srcHeight / widthScale);
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} else {
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destWidth = (int) (srcWidth / heightScale);
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destHeight = targetHeight;
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}
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float scale = 1;
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if ((!stretch && destWidth < srcWidth && destHeight < srcHeight) || (stretch && destWidth != srcWidth && destHeight != srcHeight)) {
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scale = (float) destWidth / srcWidth;
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}
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return scale;
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}
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}
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