--- old/src/java.desktop/share/classes/com/sun/imageio/plugins/png/PNGImageReader.java 2018-04-05 15:20:47.337898000 +0530 +++ new/src/java.desktop/share/classes/com/sun/imageio/plugins/png/PNGImageReader.java 2018-04-05 15:20:47.009734000 +0530 @@ -698,10 +698,12 @@ readHeader(); /* - * Optimization: We can skip the remaining metadata if the - * ignoreMetadata flag is set, and only if this is not a palette - * image (in that case, we need to read the metadata to get the - * tRNS chunk, which is needed for the getImageTypes() method). + * Optimization: We can skip reading metadata if ignoreMetadata + * flag is set and colorType is not PNG_COLOR_PALETTE. However, + * we parse tRNS chunk to retrieve the transparent color from the + * metadata. Doing so, helps PNGImageReader to appropriately + * identify and set transparent pixels in the decoded image for + * colorType PNG_COLOR_RGB and PNG_COLOR_GRAY. */ int colorType = metadata.IHDR_colorType; if (ignoreMetadata && colorType != PNG_COLOR_PALETTE) { @@ -717,10 +719,19 @@ int chunkType = stream.readInt(); if (chunkType == IDAT_TYPE) { - // We've reached the image data + // We've reached the first IDAT chunk position stream.skipBytes(-8); imageStartPosition = stream.getStreamPosition(); + /* + * According to PNG specification tRNS chunk must + * precede the first IDAT chunk. So we can stop + * reading metadata. + */ break; + } else if (chunkType == tRNS_TYPE) { + parse_tRNS_chunk(chunkLength); + // After parsing tRNS chunk we will skip 4 CRC bytes + stream.skipBytes(4); } else { // Skip the chunk plus the 4 CRC bytes that follow stream.skipBytes(chunkLength + 4); @@ -1266,7 +1277,24 @@ break; } - if (useSetRect) { + /* + * In case of colortype PNG_COLOR_RGB or PNG_COLOR_GRAY + * if we have transparent pixel information from tRNS chunk + * we need to consider that also and store proper information + * in alpha channel. + * + * Also we create destination image with extra alpha channel + * in getImageTypes() when we have tRNS chunk for colorType + * PNG_COLOR_RGB or PNG_COLOR_GRAY. + */ + boolean tRNSTransparentPixelPresent = + theImage.getSampleModel().getNumBands() == inputBands + 1 && + metadata.tRNS_present && + (metadata.tRNS_colorType == PNG_COLOR_RGB || + metadata.tRNS_colorType == PNG_COLOR_GRAY); + if (useSetRect && + !tRNSTransparentPixelPresent) + { imRas.setRect(updateMinX, dstY, passRow); } else { int newSrcX = srcX; @@ -1281,7 +1309,47 @@ ps[b] = scale[b][ps[b]]; } } - imRas.setPixel(dstX, dstY, ps); + if (tRNSTransparentPixelPresent) + { + /* + * Create intermediate array to fill the extra + * alpha channel for each pixel. + */ + int[] temp = new int[inputBands + 1]; + if (metadata.tRNS_colorType == PNG_COLOR_RGB) { + temp[0] = ps[0]; + temp[1] = ps[1]; + temp[2] = ps[2]; + if (ps[0] == metadata.tRNS_red && + ps[1] == metadata.tRNS_green && + ps[2] == metadata.tRNS_blue) + { + temp[3] = 0; + } else { + if (bitDepth < 16) { + temp[3] = 255; + } else { + temp[3] = 65535; + } + } + } else { + // when tRNS_colorType is PNG_COLOR_GRAY + temp[0] = ps[0]; + if (ps[0] == metadata.tRNS_gray) + { + temp[1] = 0; + } else { + if (bitDepth < 16) { + temp[1] = 255; + } else { + temp[1] = 65535; + } + } + } + imRas.setPixel(dstX, dstY, temp); + } else { + imRas.setPixel(dstX, dstY, ps); + } newSrcX += srcXStep; } } @@ -1422,9 +1490,20 @@ // how many bands are in the image, so perform checking // of the read param. int colorType = metadata.IHDR_colorType; - checkReadParamBandSettings(param, - inputBandsForColorType[colorType], - theImage.getSampleModel().getNumBands()); + if (theImage.getSampleModel().getNumBands() == + inputBandsForColorType[colorType] + 1 && + metadata.tRNS_present && + (metadata.tRNS_colorType == PNG_COLOR_RGB || + metadata.tRNS_colorType == PNG_COLOR_GRAY)) + { + checkReadParamBandSettings(param, + inputBandsForColorType[colorType] + 1, + theImage.getSampleModel().getNumBands()); + } else { + checkReadParamBandSettings(param, + inputBandsForColorType[colorType], + theImage.getSampleModel().getNumBands()); + } clearAbortRequest(); processImageStarted(0); @@ -1506,7 +1585,27 @@ } switch (colorType) { + /* + * In case of PNG_COLOR_RGB or PNG_COLOR_GRAY, if we + * have transparent pixel information in tRNS chunk + * we create destination image having alpha channel. + */ case PNG_COLOR_GRAY: + readMetadata(); // Need tRNS chunk + + if (metadata.tRNS_present && + metadata.tRNS_colorType == PNG_COLOR_GRAY) + { + gray = ColorSpace.getInstance(ColorSpace.CS_GRAY); + bandOffsets = new int[2]; + bandOffsets[0] = 0; + bandOffsets[1] = 1; + l.add(ImageTypeSpecifier.createInterleaved(gray, + bandOffsets, + dataType, + true, + false)); + } // Packed grayscale l.add(ImageTypeSpecifier.createGrayscale(bitDepth, dataType, @@ -1514,7 +1613,15 @@ break; case PNG_COLOR_RGB: + readMetadata(); // Need tRNS chunk + if (bitDepth == 8) { + if (metadata.tRNS_present && + metadata.tRNS_colorType == PNG_COLOR_RGB) + { + l.add(ImageTypeSpecifier.createFromBufferedImageType( + BufferedImage.TYPE_4BYTE_ABGR)); + } // some standard types of buffered images // which can be used as destination l.add(ImageTypeSpecifier.createFromBufferedImageType( @@ -1527,6 +1634,20 @@ BufferedImage.TYPE_INT_BGR)); } + if (metadata.tRNS_present && + metadata.tRNS_colorType == PNG_COLOR_RGB) + { + rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB); + bandOffsets = new int[4]; + bandOffsets[0] = 0; + bandOffsets[1] = 1; + bandOffsets[2] = 2; + bandOffsets[3] = 3; + + l.add(ImageTypeSpecifier. + createInterleaved(rgb, bandOffsets, + dataType, true, false)); + } // Component R, G, B rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB); bandOffsets = new int[3];