BaseImageDecoder.java 文件源码

protected Options prepareDecodingOptions(ImageSize imageSize, ImageDecodingInfo decodingInfo) {
    int scale;
    ImageScaleType scaleType = decodingInfo.getImageScaleType();
    if (scaleType == ImageScaleType.NONE) {
        scale = 1;
    } else if (scaleType == ImageScaleType.NONE_SAFE) {
        scale = ImageSizeUtils.computeMinImageSampleSize(imageSize);
    } else {
        boolean powerOf2;
        ImageSize targetSize = decodingInfo.getTargetSize();
        if (scaleType == ImageScaleType.IN_SAMPLE_POWER_OF_2) {
            powerOf2 = true;
        } else {
            powerOf2 = false;
        }
        scale = ImageSizeUtils.computeImageSampleSize(imageSize, targetSize, decodingInfo.getViewScaleType(), powerOf2);
    }
    if (scale > 1 && this.loggingEnabled) {
        L.d(LOG_SUBSAMPLE_IMAGE, imageSize, imageSize.scaleDown(scale), Integer.valueOf(scale), decodingInfo.getImageKey());
    }
    Options decodingOptions = decodingInfo.getDecodingOptions();
    decodingOptions.inSampleSize = scale;
    return decodingOptions;
}