public IIOMetadata getDefaultImageMetadata(ImageTypeSpecifier imageType, ImageWriteParam param) { GIFWritableImageMetadata imageMetadata = new GIFWritableImageMetadata(); // Image dimensions SampleModel sampleModel = imageType.getSampleModel(); Rectangle sourceBounds = new Rectangle(sampleModel.getWidth(), sampleModel.getHeight()); Dimension destSize = new Dimension(); computeRegions(sourceBounds, destSize, param); imageMetadata.imageWidth = destSize.width; imageMetadata.imageHeight = destSize.height; // Interlacing if (param != null && param.canWriteProgressive() && param.getProgressiveMode() == ImageWriteParam.MODE_DISABLED) { imageMetadata.interlaceFlag = false; } else { imageMetadata.interlaceFlag = true; } // Local color table ColorModel colorModel = imageType.getColorModel(); imageMetadata.localColorTable = createColorTable(colorModel, sampleModel); // Transparency if (colorModel instanceof IndexColorModel) { int transparentIndex = ((IndexColorModel) colorModel).getTransparentPixel(); if (transparentIndex != -1) { imageMetadata.transparentColorFlag = true; imageMetadata.transparentColorIndex = transparentIndex; } } return imageMetadata; }