jpegimagewriter.java

java jdk 1.4的源码

                            if (!alpha) {
                                if (jfif != null) {
                                    outCsType = JPEG.JCS_YCbCr;
                                    if (JPEG.isNonStandardICC(cs) 
                                        || ((cs instanceof ICC_ColorSpace) 
                                            && (jfif.iccSegment != null))) {
                                        iccProfile = 
                                            ((ICC_ColorSpace) cs).getProfile();
                                    }
                                } else if (adobe != null) {
                                    switch (adobe.transform) { 
                                    case JPEG.ADOBE_UNKNOWN:
                                        outCsType = JPEG.JCS_RGB;
                                        break;
                                    case JPEG.ADOBE_YCC:
                                        outCsType = JPEG.JCS_YCbCr;
                                        break;
                                    default:
                                        warningOccurred
                                        (WARNING_IMAGE_METADATA_ADOBE_MISMATCH);
                                        newAdobeTransform = JPEG.ADOBE_UNKNOWN;
                                        outCsType = JPEG.JCS_RGB;
                                        break;
                                    }
                                } else {
                                    // consult the ids
                                    int outCS = sof.getIDencodedCSType();
                                    // if they don't resolve it,
                                    // consult the sampling factors
                                    if (outCS != JPEG.JCS_UNKNOWN) {
                                        outCsType = outCS;
                                    } else {
                                        boolean subsampled = 
                                        isSubsampled(sof.componentSpecs);
                                        if (subsampled) {
                                            outCsType = JPEG.JCS_YCbCr;
                                        } else {
                                            outCsType = JPEG.JCS_RGB;
                                        }
                                    }
                                }
                            } else { // RGBA
                                if (jfif != null) {
                                    ignoreJFIF = true;
                                    warningOccurred
                                    (WARNING_IMAGE_METADATA_JFIF_MISMATCH);
                                }
                                if (adobe != null) {
                                    if (adobe.transform 
                                        != JPEG.ADOBE_UNKNOWN) {
                                        newAdobeTransform = JPEG.ADOBE_UNKNOWN;
                                        warningOccurred
                                        (WARNING_IMAGE_METADATA_ADOBE_MISMATCH);
                                    }
                                    outCsType = JPEG.JCS_RGBA;
                                } else {
                                    // consult the ids
                                    int outCS = sof.getIDencodedCSType();
                                    // if they don't resolve it,
                                    // consult the sampling factors
                                    if (outCS != JPEG.JCS_UNKNOWN) {
                                        outCsType = outCS;
                                    } else {
                                        boolean subsampled = 
                                        isSubsampled(sof.componentSpecs);
                                        outCsType = subsampled ? 
                                            JPEG.JCS_YCbCrA : JPEG.JCS_RGBA;
                                    }
                                }
                            }
                            break;
                        case ColorSpace.TYPE_3CLR:
                            if (cs == JPEG.YCC) {
                                if (!alpha) {
                                    if (jfif != null) {
                                        convertTosRGB = true;
                                        convertOp = 
                                        new ColorConvertOp(cs, 
                                                           JPEG.sRGB, 
                                                           null);
                                        outCsType = JPEG.JCS_YCbCr;
                                    } else if (adobe != null) {
                                        if (adobe.transform 
                                            != JPEG.ADOBE_YCC) {
                                            newAdobeTransform = JPEG.ADOBE_YCC;
                                            warningOccurred
                                            (WARNING_IMAGE_METADATA_ADOBE_MISMATCH);
                                        }
                                        outCsType = JPEG.JCS_YCC;
                                    } else {
                                        outCsType = JPEG.JCS_YCC;
                                    }
                                } else { // PhotoYCCA
                                    if (jfif != null) {
                                        ignoreJFIF = true;
                                        warningOccurred
                                        (WARNING_IMAGE_METADATA_JFIF_MISMATCH);
                                    } else if (adobe != null) {
                                        if (adobe.transform 
                                            != JPEG.ADOBE_UNKNOWN) {
                                            newAdobeTransform 
                                            = JPEG.ADOBE_UNKNOWN;
                                            warningOccurred
                                            (WARNING_IMAGE_METADATA_ADOBE_MISMATCH);
                                        }
                                    }
                                    outCsType = JPEG.JCS_YCCA;
                                }
                            }
                        }
                    }
                } // else no dest, metadata, not an image.  Defaults ok
            }
        }

        boolean metadataProgressive = false;
        int [] scans = null;

        if (metadata != null) {
            if (sof == null) {
                sof = (SOFMarkerSegment) metadata.findMarkerSegment
                    (SOFMarkerSegment.class, true);
            }
            if ((sof != null) && (sof.tag == JPEG.SOF2)) {
                metadataProgressive = true;
                if (progressiveMode == ImageWriteParam.MODE_COPY_FROM_METADATA) {
                    scans = collectScans(metadata, sof);  // Might still be null
                } else {
                    numScans = 0;
                }
            }
            if (jfif == null) {
                jfif = (JFIFMarkerSegment) metadata.findMarkerSegment
                    (JFIFMarkerSegment.class, true);
            }
        }

        thumbnails = image.getThumbnails();
        int numThumbs = image.getNumThumbnails();
        forceJFIF = false;
        // determine if thumbnails can be written
        // If we are going to add a default JFIF marker segment,
        // then thumbnails can be written
        if (!writeDefaultJFIF) {
            // If there is no metadata, then we can't write thumbnails
            if (metadata == null) {
                thumbnails = null;
                if (numThumbs != 0) {
                    warningOccurred(WARNING_IGNORING_THUMBS);
                }
            } else {
                // There is metadata
                // If we are writing a raster or subbands,
                // then the user must specify JFIF on the metadata
                if (fullImage == false) {
                    if (jfif == null) {
                        thumbnails = null;  // Or we can't include thumbnails
                        if (numThumbs != 0) {
                            warningOccurred(WARNING_IGNORING_THUMBS);
                        }
                    }
                } else {  // It is a full image, and there is metadata
                    if (jfif == null) {  // Not JFIF
                        // Can it have JFIF?
                        if ((outCsType == JPEG.JCS_GRAYSCALE)
                            || (outCsType == JPEG.JCS_YCbCr)) {
                            if (numThumbs != 0) {
                                forceJFIF = true;
                                warningOccurred(WARNING_FORCING_JFIF);
                            }
                        } else {  // Nope, not JFIF-compatible
                            thumbnails = null;
                            if (numThumbs != 0) {
                                warningOccurred(WARNING_IGNORING_THUMBS);
                            }
                        }
                    }
                }
            }
        }

        // Set up a boolean to indicate whether we need to call back to 
        // write metadata
        boolean haveMetadata = 
            ((metadata != null) || writeDefaultJFIF || writeAdobe);

        // Now that we have dealt with metadata, finalize our tables set up

        // Are we going to write tables?  By default, yes.
        boolean writeDQT = true;
        boolean writeDHT = true;

        // But if the metadata has no tables, no.
        DQTMarkerSegment dqt = null;
        DHTMarkerSegment dht = null;

        int restartInterval = 0;

        if (metadata != null) {
            dqt = (DQTMarkerSegment) metadata.findMarkerSegment
                (DQTMarkerSegment.class, true);
            dht = (DHTMarkerSegment) metadata.findMarkerSegment
                (DHTMarkerSegment.class, true);
            DRIMarkerSegment dri = 
                (DRIMarkerSegment) metadata.findMarkerSegment
                (DRIMarkerSegment.class, true);
            if (dri != null) {
                restartInterval = dri.restartInterval;
            }

            if (dqt == null) {
                writeDQT = false;
            }
            if (dht == null) {
                writeDHT = false;  // Ignored if optimizeHuffman is true
            }
        }

        // Whether we write tables or not, we need to figure out which ones 
        // to use
        if (qTables == null) { // Get them from metadata, or use defaults
            if (dqt != null) {
                qTables = collectQTablesFromMetadata(metadata);
            } else if (streamQTables != null) { 
                qTables = streamQTables;
            } else if ((jparam != null) && (jparam.areTablesSet())) {
                qTables = jparam.getQTables();
            } else {
                qTables = JPEG.getDefaultQTables();
            }

        }

        // If we are optimizing, we don't want any tables.
        if (optimizeHuffman == false) {
            // If they were for progressive scans, we can't use them.
            if ((dht != null) && (metadataProgressive == false)) {
                DCHuffmanTables = collectHTablesFromMetadata(metadata, true);
                ACHuffmanTables = collectHTablesFromMetadata(metadata, false);
            } else if (streamDCHuffmanTables != null) { 
                DCHuffmanTables = streamDCHuffmanTables;
                ACHuffmanTables = streamACHuffmanTables;
            } else if ((jparam != null) && (jparam.areTablesSet())) {
                DCHuffmanTables = jparam.getDCHuffmanTables();
                ACHuffmanTables = jparam.getACHuffmanTables();
            } else {
                DCHuffmanTables = JPEG.getDefaultHuffmanTables(true);
                ACHuffmanTables = JPEG.getDefaultHuffmanTables(false);
            }
        }

        // By default, ids are 1 - N, no subsampling
        int [] componentIds = new int[numBandsUsed];
        int [] HsamplingFactors = new int[numBandsUsed];
        int [] VsamplingFactors = new int[numBandsUsed];
        int [] QtableSelectors = new int[numBandsUsed];
        for (int i = 0; i < numBandsUsed; i++) {
            componentIds[i] = i+1; // JFIF compatible
            HsamplingFactors[i] = 1;
            VsamplingFactors[i] = 1;
            QtableSelectors[i] = 0;
        }

        // Now override them with the contents of sof, if there is one,
        if (sof != null) {
            for (int i = 0; i < numBandsUsed; i++) {
                if (forceJFIF == false) {  // else use JFIF-compatible default
                    componentIds[i] = sof.componentSpecs[i].componentId;
                }
                HsamplingFactors[i] = sof.componentSpecs[i].HsamplingFactor;
                VsamplingFactors[i] = sof.componentSpecs[i].VsamplingFactor;
                QtableSelectors[i] = sof.componentSpecs[i].QtableSelector;
            }
        }

        sourceXOffset += gridX;
        sourceWidth -= gridX;
        sourceYOffset += gridY;
        sourceHeight -= gridY;

        int destWidth = (sourceWidth + periodX - 1)/periodX;
        int destHeight = (sourceHeight + periodY - 1)/periodY;

        // Create an appropriate 1-line databuffer for writing
        int lineSize = sourceWidth*numBandsUsed;
        
        DataBufferByte buffer = new DataBufferByte(lineSize);

        // Create a raster from that
        int [] bandOffs = JPEG.bandOffsets[numBandsUsed-1];
        
        raster = Raster.createInterleavedRaster(buffer, 
                                                sourceWidth, 1, 
                                                lineSize,
                                                numBandsUsed,
                                                bandOffs,
                                                null);

        // Call the writer, who will call back for every scanline

        processImageStarted(currentImage);
            
        boolean aborted = false;

        if (debug) {
            System.out.println("inCsType: " + inCsType);
            System.out.println("outCsType: " + outCsType);
        }

        aborted = writeImage(structPointer,
                             buffer.getData(), 
                             inCsType, outCsType,
                             numBandsUsed,
                             bandSizes,
                             sourceWidth,
                             destWidth, destHeight,
                             periodX, periodY,
                             qTables,