cmsimagescaler.java

cms是开源的框架

            result.append(filter);
            if (i.hasNext()) {
                result.append(':');
            }
        }
        return result.toString();
    }

    /**
     * Returns the height.<p>
     *
     * @return the height
     */
    public int getHeight() {

        return m_height;
    }

    /**
     * Returns the image type from the given file name based on the file suffix (extension)
     * and the available image writers.<p>
     * 
     * For example, for the file name "opencms.gif" the type is GIF, for 
     * "opencms.jpg" is is "JPEG" etc.<p> 
     * 
     * In case the input filename has no suffix, or there is no known image writer for the format defined
     * by the suffix, <code>null</code> is returned.<p>
     * 
     * Any non-null result can be used if an image type input value is required.<p>
     * 
     * @param filename the file name to get the type for
     *  
     * @return the image type from the given file name based on the suffix and the available image writers, 
     *      or null if no image writer is available for the format 
     */
    public String getImageType(String filename) {

        return Simapi.getImageType(filename);
    }

    /**
     * Returns the maximum image size (width * height) to apply image blurring when downscaling images.<p>
     * 
     * Image blurring is required to achive the best results for downscale operatios when the target image size 
     * is 2 times or more smaller then the original image size. This parameter controls the maximum size (width * height) of an 
     * image that is blurred before it is downscaled. If the image is larger, no blurring is done. 
     * However, image blurring is an expensive operation in both CPU usage and memory consumption. 
     * Setting the blur size to large may case "out of memory" errors.<p>
     * 
     * @return the maximum image size (width * height) to apply image blurring when downscaling images
     */
    public int getMaxBlurSize() {

        return m_maxBlurSize;
    }

    /**
     * Returns the image pixel count, that is the image with multiplied by the image height.<p>
     * 
     * If this scalier is not valid (see {@link #isValid()}) the result is undefined.<p>
     * 
     * @return the image pixel count, that is the image with multiplied by the image height
     */
    public int getPixelCount() {

        return m_width * m_height;
    }

    /**
     * Returns the position.<p>
     *
     * @return the position
     */
    public int getPosition() {

        return m_position;
    }

    /**
     * Returns the image saving quality in percent (0 - 100).<p>
     * 
     * This is used oly if applicable, for example when saving JPEG images.<p>
     *
     * @return the image saving quality in percent
     */
    public int getQuality() {

        return m_quality;
    }

    /**
     * Returns the image rendering mode constant.<p>
     *
     * Possible values are:<dl>
     * <dt>{@link Simapi#RENDER_QUALITY} (default)</dt>
     * <dd>Use best possible image processing - this may be slow sometimes.</dd>
     * 
     * <dt>{@link Simapi#RENDER_SPEED}</dt>
     * <dd>Fastest image processing but worse results - use this for thumbnails or where speed is more important then quality.</dd>
     * 
     * <dt>{@link Simapi#RENDER_MEDIUM}</dt>
     * <dd>Use default rendering hints from JVM - not recommended since it's almost as slow as the {@link Simapi#RENDER_QUALITY} mode.</dd></dl>
     *
     * @return the image rendering mode constant
     */
    public int getRenderMode() {

        return m_renderMode;
    }

    /**
     * Returns a new image scaler that is a rescaler from the <code>this</code> scaler 
     * size to the given target scaler size.<p>
     * 
     * The height of the target image is calculated in proportion 
     * to the original image width. If the width of the the original image is not known, 
     * the target image width is calculated in proportion to the original image height.<p>
     * 
     * @param target the image scaler that holds the target image dimensions
     * 
     * @return a new image scaler that is a rescale from the <code>this</code> scaler 
     *      size to the given target scaler size.<p>
     */
    public CmsImageScaler getReScaler(CmsImageScaler target) {

        int height = target.getHeight();
        int width = target.getWidth();

        if ((width > 0) && (getWidth() > 0)) {
            // width is known, calculate height
            float scale = (float)width / (float)getWidth();
            height = Math.round(getHeight() * scale);
        } else if ((height > 0) && (getHeight() > 0)) {
            // height is known, calculate width
            float scale = (float)height / (float)getHeight();
            width = Math.round(getWidth() * scale);
        } else if (isValid() && !target.isValid()) {
            // scaler is not valid but original is, so use original size of image
            width = getWidth();
            height = getHeight();
        }

        if ((target.getType() == 1) && (!target.isValid())) {
            // "no upscale" has been requested, only one target dimension was given
            if ((target.getWidth() > 0) && (getWidth() < width)) {
                // target width was given, target image should have this width 
                height = getHeight();
            } else if ((target.getHeight() > 0) && (getHeight() < height)) {
                // target height was given, target image should have this height
                width = getWidth();
            }
        }

        // now create and initialize the result scaler
        return new CmsImageScaler(target, width, height);
    }

    /**
     * Returns the type.<p>
     * 
     * Possible values are:<dl>
     * 
     * <dt>0 (default): Scale to exact target size with background padding</dt><dd><ul>
     * <li>enlarge image to fit in target size (if required)
     * <li>reduce image to fit in target size (if required)
     * <li>keep image aspect ratio / propotions intact
     * <li>fill up with bgcolor to reach exact target size
     * <li>fit full image inside target size (only applies if reduced)</ul></dd>
     *
     * <dt>1: Thumbnail generation mode (like 0 but no image enlargement)</dt><dd><ul>
     * <li>dont't enlarge image
     * <li>reduce image to fit in target size (if required)
     * <li>keep image aspect ratio / propotions intact
     * <li>fill up with bgcolor to reach exact target size
     * <li>fit full image inside target size (only applies if reduced)</ul></dd>
     *
     * <dt>2: Scale to exact target size, crop what does not fit</dt><dd><ul>
     * <li>enlarge image to fit in target size (if required)
     * <li>reduce image to fit in target size (if required)
     * <li>keep image aspect ratio / propotions intact
     * <li>fit full image inside target size (crop what does not fit)</ul></dd>
     *
     * <dt>3: Scale and keep image propotions, target size variable</dt><dd><ul>
     * <li>enlarge image to fit in target size (if required)
     * <li>reduce image to fit in target size (if required)
     * <li>keep image aspect ratio / propotions intact
     * <li>scaled image will not be padded or cropped, so target size is likley not the exact requested size</ul></dd>
     *
     * <dt>4: Don't keep image propotions, use exact target size</dt><dd><ul>
     * <li>enlarge image to fit in target size (if required)
     * <li>reduce image to fit in target size (if required)
     * <li>don't keep image aspect ratio / propotions intact
     * <li>the image will be scaled exactly to the given target size and likley will be loose proportions</ul></dd>
     * </dl>
     * 
     * @return the type
     */
    public int getType() {

        return m_type;
    }

    /**
     * Returns the width.<p>
     *
     * @return the width
     */
    public int getWidth() {

        return m_width;
    }

    /**
     * Returns a new image scaler that is a width based downscale from the size of <code>this</code> scaler 
     * to the given scaler size.<p>
     * 
     * If no downscale from this to the given scaler is required because the width of <code>this</code>
     * scaler is not larger than the target width, then the image dimensions of <code>this</code> scaler 
     * are unchanged in the result scaler. No upscaling is done!<p>
     * 
     * @param downScaler the image scaler that holds the downscaled target image dimensions
     * 
     * @return a new image scaler that is a downscale from the size of <code>this</code> scaler 
     *      to the given target scaler size
     */
    public CmsImageScaler getWidthScaler(CmsImageScaler downScaler) {

        int width = downScaler.getWidth();
        int height;

        if (getWidth() > width) {
            // width is too large, re-calculate height
            float scale = (float)width / (float)getWidth();
            height = Math.round(getHeight() * scale);
        } else {
            // width is ok
            width = getWidth();
            height = getHeight();
        }

        // now create and initialize the result scaler
        return new CmsImageScaler(downScaler, width, height);
    }

    /**
     * @see java.lang.Object#hashCode()
     */
    public int hashCode() {

        return toString().hashCode();
    }

    /**
     * Returns <code>true</code> if this image scaler must be downscaled when compared to the
     * given "downscale" image scaler.<p>
     *
     * If either <code>this</code> scaler or the given <code>downScaler</code> is invalid according to
     * {@link #isValid()}, then <code>false</code> is returned.<p>
     * 
     * The use case: <code>this</code> scaler represents an image (that is contains width and height of 
     * an image). The <code>downScaler</code> represents the maximum wanted image. The scalers
     * are compared and if the image represented by <code>this</code> scaler is too large,
     * <code>true</code> is returned. Image orientation is ignored, so for example an image with 600x800 pixel 
     * will NOT be downscaled if the target size is 800x600 but kept unchanged.<p>
     * 
     * @param downScaler the downscaler to compare this image scaler with
     * 
     * @return <code>true</code> if this image scaler must be downscaled when compared to the
     *      given "downscale" image scaler
     */
    public boolean isDownScaleRequired(CmsImageScaler downScaler) {

        if ((downScaler == null) || !isValid() || !downScaler.isValid()) {
            // one of the scalers is invalid
            return false;
        }

        if (getPixelCount() < (downScaler.getPixelCount() / 2)) {
            // the image has much less pixels then the target, so don't downscale
            return false;
        }

        int downWidth = downScaler.getWidth();
        int downHeight = downScaler.getHeight();
        if (downHeight > downWidth) {
            // normalize image orientation - the width should always be the large side
            downWidth = downHeight;
            downHeight = downScaler.getWidth();
        }
        int height = getHeight();
        int width = getWidth();
        if (height > width) {
            // normalize image orientation - the width should always be the large side
            width = height;
            height = getWidth();
        }

        return (width > downWidth) || (height > downHeight);
    }

    /**
     * Returns <code>true</code> if all required parameters are available.<p>
     * 
     * Required parameters are "h" (height), and "w" (width).<p>
     * 
     * @return <code>true</code> if all required parameters are available
     */
    public boolean isValid() {

        return (m_width > 0) && (m_height > 0);
    }

    /**
     * Returns a scaled version of the given image byte content according this image scalers parameters.<p>
     *  
     * @param content the image byte content to scale
     * @param rootPath the root path of the image file in the VFS
     * 
     * @return a scaled version of the given image byte content according to the provided scaler parameters
     */
    public byte[] scaleImage(byte[] content, String rootPath) {

        byte[] result = content;

        RenderSettings renderSettings;
        if ((m_renderMode == 0) && (m_quality == 0)) {
            // use default render mode and quality
            renderSettings = new RenderSettings(Simapi.RENDER_QUALITY);
        } else {
            // use special render mode and/or quality
            renderSettings = new RenderSettings(m_renderMode);
            if (m_quality != 0) {
                renderSettings.setCompressionQuality(m_quality / 100f);
            }
        }
        // set max blur siuze
        renderSettings.setMaximumBlurSize(m_maxBlurSize);
        // new create the scaler
        Simapi scaler = new Simapi(renderSettings);
        // calculate a valid image type supported by the imaging libary (e.g. "JPEG", "GIF")
        String imageType = Simapi.getImageType(rootPath);
        if (imageType == null) {
            // no type given, maybe the name got mixed up
            String mimeType = OpenCms.getResourceManager().getMimeType(rootPath, null, null);
            // check if this is another known mime type, if so DONT use it (images should not be named *.pdf)
            if (mimeType == null) {
                // no mime type found, use JPEG format to write images to the cache         
                imageType = Simapi.TYPE_JPEG;
            }
        }
        if (imageType == null) {
            // unknown type, unable to scale the image
            if (LOG.isDebugEnabled()) {
                LOG.debug(Messages.get().getBundle().key(Messages.ERR_UNABLE_TO_SCALE_IMAGE_2, rootPath, toString()));
            }
            return result;
        }
        try {
            BufferedImage image = Simapi.read(content);

            Color color = getColor();

            if (!m_filters.isEmpty()) {
                Iterator i = m_filters.iterator();
                while (i.hasNext()) {
                    String filter = (String)i.next();
                    if (FILTER_GRAYSCALE.equals(filter)) {
                        // add a grayscale filter
                        GrayscaleFilter grayscaleFilter = new GrayscaleFilter();
                        renderSettings.addImageFilter(grayscaleFilter);
                    } else if (FILTER_SHADOW.equals(filter)) {
                        // add a drop shadow filter
                        ShadowFilter shadowFilter = new ShadowFilter();
                        shadowFilter.setXOffset(5);
                        shadowFilter.setYOffset(5);
                        shadowFilter.setOpacity(192);
                        shadowFilter.setBackgroundColor(color.getRGB());
                        color = Simapi.COLOR_TRANSPARENT;
                        renderSettings.setTransparentReplaceColor(Simapi.COLOR_TRANSPARENT);
                        renderSettings.addImageFilter(shadowFilter);
                    }
                }
            }

            switch (getType()) {