imagetogif.java

JavaExplorer是一个独立于平台的浏览器

                        continue;
                    }

                    pixCol[k2] = word0;

                    break;
                }
            }
        } catch (Exception ex) {
            return false;
        }

        return true;
    }

    /**
     *@param  word0  Description of the Parameter
     *@return        Description of the Return
     *      Value
     */
    public boolean lzwOutput(short word0) {
        try {
            lzwData |= (word0 << lzwBits);

            for (lzwBits += sActCodeSize; lzwBits >= 8;) {
                Block[BlockPos++] = (byte) (lzwData & 0xff);
                Block[0]++;
                lzwData >>= 8;
                lzwBits -= 8;

                if (BlockPos == 256) {
                    for (int i = 0; i < 256; i++) {
                        dataOut.writeByte(Block[i]);
                    }

                    Block[0] = 0;
                    BlockPos = 1;
                }
            }

            return true;
        } catch (Exception ex) {
            return false;
        }
    }

    /**
     *@return               Description of
     *      the Return Value
     *@throws  IOException  Description of
     *      the Exception
     */
    public boolean openGif() throws IOException {
        try {
            dataOut = new DataOutputStream(output);
        } catch (Exception ex) {
            return false;
        }

        return true;
    }

    /**
     */
    public void startProc() {
        try {
            code = new short[5003];
            prefix = new short[5003];
            codeCharacter = new short[5003];
            Block = new short[256];

            if ((image != null) && getImageInfo() && openGif() && calcGif()) {
                if (closeGif()) {
                    if (message) {
                        System.out.println("\n Picture is available!");

                        return;
                    }
                } else if (message) {
                    System.out.println("\n Error, Picture is NOT available!");
                }

                return;
            }
        } catch (Exception exception) {
            System.out.println(String.valueOf(exception));
        }
    }

    /**
     *@return    Description of the Return
     *      Value
     */
    public boolean writeDataBlocks() {
        int[] ai = {
            0, 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, 8191
        };

        try {
            int j = (flagLSD & 0x7) + 1;

            if (j > 2) {
                sOriginalCodeSize = (short) j;
            } else {
                sOriginalCodeSize = 2;
            }

            dataOut.writeByte((byte) sOriginalCodeSize);
            CalcSpecialCodes();
            ClearCompressionTable();
            Block[0] = 0;
            BlockPos = 1;
            lzwData = 0;
            lzwBits = 0;

            if (!lzwOutput(clearCode)) {
                return false;
            }

            int l = 0;
            int i = l * imgWidth;
            short word3 = (short) (pixCol[i++] & 0xff);
            int k = 1;

            while (l < imgHeight) {
                short word2 = pixCol[i++];
                short word0 = FindSlot(word3, word2);

                if (code[word0] != -1) {
                    word3 = code[word0];
                } else {
                    if (freeSlot <= (ai[sActCodeSize] + 1)) {
                        code[word0] = freeSlot++;
                        prefix[word0] = word3;
                        codeCharacter[word0] = word2;
                    }

                    if (!lzwOutput(word3)) {
                        return false;
                    }

                    word3 = word2;

                    if ((freeSlot > (ai[sActCodeSize] + 1)) ||
                            (freeSlot == 4096)) {
                        if (sActCodeSize < 12) {
                            sActCodeSize++;
                        } else {
                            if (!lzwOutput(clearCode)) {
                                return false;
                            }

                            sActCodeSize = sOriginalCodeSize;
                            CalcSpecialCodes();
                            ClearCompressionTable();
                        }
                    }
                }

                if (++k == imgWidth) {
                    k = 0;

                    if (++l < imgHeight) {
                        i = l * imgWidth;
                    }
                }
            }

            if (!lzwOutput(word3)) {
                return false;
            }

            if (!lzwOutput((short) 0)) {
                return false;
            }

            if (!lzwOutput(endCode)) {
                return false;
            }

            if (!lzwOutput((short) 0)) {
                return false;
            }

            if (Block[0] != 0) {
                dataOut.writeByte(Block[0]);

                for (short word1 = 1; word1 <= Block[0];) {
                    dataOut.writeByte(Block[word1++]);
                }

                dataOut.writeByte(0);
            }

            return true;
        } catch (Exception ex) {
            return false;
        }
    }

    /**
     *@return    Description of the Return
     *      Value
     */
    public boolean writeGlobalPalette() {
        int j = 1;

        for (int i = palSize - 1; (i >>= 1) > 0;) {
            j++;
        }

        try {
            for (int k = 0; k < palSize; k++) {
                Color color = new Color(palArr[k]);
                dataOut.writeByte(color.getRed());
                dataOut.writeByte(color.getGreen());
                dataOut.writeByte(color.getBlue());
            }

            for (int l = palSize; l < (1 << j); l++) {
                Color color1 = new Color(palArr[0]);
                dataOut.writeByte(color1.getRed());
                dataOut.writeByte(color1.getGreen());
                dataOut.writeByte(color1.getBlue());
            }
        } catch (Exception ex) {
            return false;
        }

        return true;
    }

    /**
     *@return    Description of the Return
     *      Value
     */
    public boolean writeHeader() {
        try {
            dataOut.writeBytes("GIF87a");
        } catch (Exception ex) {
            return false;
        }

        return true;
    }

    /**
     *@return    Description of the Return
     *      Value
     */
    public boolean writeImageDescriptor() {
        try {
            byte byte0 = (byte) (flagLSD & 0x7);
            dataOut.writeByte(44);
            dataOut.writeChar(0);
            dataOut.writeChar(0);
            dataOut.writeChar(MSBtoLSB(imgWidth));
            dataOut.writeChar(MSBtoLSB(imgHeight));
            dataOut.writeByte(byte0);
        } catch (Exception ex) {
            return false;
        }

        return true;
    }

    /**
     *@return    Description of the Return
     *      Value
     */
    public boolean writeLSD() {
        byte byte0 = 0;
        int i = palSize - 1;

        try {
            while ((i >>= 1) > 0) {
                byte0++;
            }

            flagLSD = (byte) (((byte0 + 8) << 4) + byte0);
            dataOut.writeChar(MSBtoLSB(imgWidth));
            dataOut.writeChar(MSBtoLSB(imgHeight));
            dataOut.writeByte(flagLSD);
            dataOut.writeByte(0);
            dataOut.writeByte(0);
        } catch (Exception ex) {
            return false;
        }

        return true;
    }
}