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Java example source code file (ImageView.java)
The ImageView.java Java example source code/* * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.swing.text.html; import java.awt.*; import java.awt.image.ImageObserver; import java.net.*; import java.util.Dictionary; import javax.swing.*; import javax.swing.text.*; import javax.swing.event.*; /** * View of an Image, intended to support the HTML <IMG> tag. * Supports scaling via the HEIGHT and WIDTH attributes of the tag. * If the image is unable to be loaded any text specified via the * <code>ALT attribute will be rendered. * <p> * While this class has been part of swing for a while now, it is public * as of 1.4. * * @author Scott Violet * @see IconView * @since 1.4 */ public class ImageView extends View { /** * If true, when some of the bits are available a repaint is done. * <p> * This is set to false as swing does not offer a repaint that takes a * delay. If this were true, a bunch of immediate repaints would get * generated that end up significantly delaying the loading of the image * (or anything else going on for that matter). */ private static boolean sIsInc = false; /** * Repaint delay when some of the bits are available. */ private static int sIncRate = 100; /** * Property name for pending image icon */ private static final String PENDING_IMAGE = "html.pendingImage"; /** * Property name for missing image icon */ private static final String MISSING_IMAGE = "html.missingImage"; /** * Document property for image cache. */ private static final String IMAGE_CACHE_PROPERTY = "imageCache"; // Height/width to use before we know the real size, these should at least // the size of <code>sMissingImageIcon and // <code>sPendingImageIcon private static final int DEFAULT_WIDTH = 38; private static final int DEFAULT_HEIGHT= 38; /** * Default border to use if one is not specified. */ private static final int DEFAULT_BORDER = 2; // Bitmask values private static final int LOADING_FLAG = 1; private static final int LINK_FLAG = 2; private static final int WIDTH_FLAG = 4; private static final int HEIGHT_FLAG = 8; private static final int RELOAD_FLAG = 16; private static final int RELOAD_IMAGE_FLAG = 32; private static final int SYNC_LOAD_FLAG = 64; private AttributeSet attr; private Image image; private Image disabledImage; private int width; private int height; /** Bitmask containing some of the above bitmask values. Because the * image loading notification can happen on another thread access to * this is synchronized (at least for modifying it). */ private int state; private Container container; private Rectangle fBounds; private Color borderColor; // Size of the border, the insets contains this valid. For example, if // the HSPACE attribute was 4 and BORDER 2, leftInset would be 6. private short borderSize; // Insets, obtained from the painter. private short leftInset; private short rightInset; private short topInset; private short bottomInset; /** * We don't directly implement ImageObserver, instead we use an instance * that calls back to us. */ private ImageObserver imageObserver; /** * Used for alt text. Will be non-null if the image couldn't be found, * and there is valid alt text. */ private View altView; /** Alignment along the vertical (Y) axis. */ private float vAlign; /** * Creates a new view that represents an IMG element. * * @param elem the element to create a view for */ public ImageView(Element elem) { super(elem); fBounds = new Rectangle(); imageObserver = new ImageHandler(); state = RELOAD_FLAG | RELOAD_IMAGE_FLAG; } /** * Returns the text to display if the image can't be loaded. This is * obtained from the Elements attribute set with the attribute name * <code>HTML.Attribute.ALT. */ public String getAltText() { return (String)getElement().getAttributes().getAttribute (HTML.Attribute.ALT); } /** * Return a URL for the image source, * or null if it could not be determined. */ public URL getImageURL() { String src = (String)getElement().getAttributes(). getAttribute(HTML.Attribute.SRC); if (src == null) { return null; } URL reference = ((HTMLDocument)getDocument()).getBase(); try { URL u = new URL(reference,src); return u; } catch (MalformedURLException e) { return null; } } /** * Returns the icon to use if the image couldn't be found. */ public Icon getNoImageIcon() { return (Icon) UIManager.getLookAndFeelDefaults().get(MISSING_IMAGE); } /** * Returns the icon to use while in the process of loading the image. */ public Icon getLoadingImageIcon() { return (Icon) UIManager.getLookAndFeelDefaults().get(PENDING_IMAGE); } /** * Returns the image to render. */ public Image getImage() { sync(); return image; } private Image getImage(boolean enabled) { Image img = getImage(); if (! enabled) { if (disabledImage == null) { disabledImage = GrayFilter.createDisabledImage(img); } img = disabledImage; } return img; } /** * Sets how the image is loaded. If <code>newValue is true, * the image we be loaded when first asked for, otherwise it will * be loaded asynchronously. The default is to not load synchronously, * that is to load the image asynchronously. */ public void setLoadsSynchronously(boolean newValue) { synchronized(this) { if (newValue) { state |= SYNC_LOAD_FLAG; } else { state = (state | SYNC_LOAD_FLAG) ^ SYNC_LOAD_FLAG; } } } /** * Returns true if the image should be loaded when first asked for. */ public boolean getLoadsSynchronously() { return ((state & SYNC_LOAD_FLAG) != 0); } /** * Convenience method to get the StyleSheet. */ protected StyleSheet getStyleSheet() { HTMLDocument doc = (HTMLDocument) getDocument(); return doc.getStyleSheet(); } /** * Fetches the attributes to use when rendering. This is * implemented to multiplex the attributes specified in the * model with a StyleSheet. */ public AttributeSet getAttributes() { sync(); return attr; } /** * For images the tooltip text comes from text specified with the * <code>ALT attribute. This is overriden to return * <code>getAltText. * * @see JTextComponent#getToolTipText */ public String getToolTipText(float x, float y, Shape allocation) { return getAltText(); } /** * Update any cached values that come from attributes. */ protected void setPropertiesFromAttributes() { StyleSheet sheet = getStyleSheet(); this.attr = sheet.getViewAttributes(this); // Gutters borderSize = (short)getIntAttr(HTML.Attribute.BORDER, isLink() ? DEFAULT_BORDER : 0); leftInset = rightInset = (short)(getIntAttr(HTML.Attribute.HSPACE, 0) + borderSize); topInset = bottomInset = (short)(getIntAttr(HTML.Attribute.VSPACE, 0) + borderSize); borderColor = ((StyledDocument)getDocument()).getForeground (getAttributes()); AttributeSet attr = getElement().getAttributes(); // Alignment. // PENDING: This needs to be changed to support the CSS versions // when conversion from ALIGN to VERTICAL_ALIGN is complete. Object alignment = attr.getAttribute(HTML.Attribute.ALIGN); vAlign = 1.0f; if (alignment != null) { alignment = alignment.toString(); if ("top".equals(alignment)) { vAlign = 0f; } else if ("middle".equals(alignment)) { vAlign = .5f; } } AttributeSet anchorAttr = (AttributeSet)attr.getAttribute(HTML.Tag.A); if (anchorAttr != null && anchorAttr.isDefined (HTML.Attribute.HREF)) { synchronized(this) { state |= LINK_FLAG; } } else { synchronized(this) { state = (state | LINK_FLAG) ^ LINK_FLAG; } } } /** * Establishes the parent view for this view. * Seize this moment to cache the AWT Container I'm in. */ public void setParent(View parent) { View oldParent = getParent(); super.setParent(parent); container = (parent != null) ? getContainer() : null; if (oldParent != parent) { synchronized(this) { state |= RELOAD_FLAG; } } } /** * Invoked when the Elements attributes have changed. Recreates the image. */ public void changedUpdate(DocumentEvent e, Shape a, ViewFactory f) { super.changedUpdate(e,a,f); synchronized(this) { state |= RELOAD_FLAG | RELOAD_IMAGE_FLAG; } // Assume the worst. preferenceChanged(null, true, true); } /** * Paints the View. * * @param g the rendering surface to use * @param a the allocated region to render into * @see View#paint */ public void paint(Graphics g, Shape a) { sync(); Rectangle rect = (a instanceof Rectangle) ? (Rectangle)a : a.getBounds(); Rectangle clip = g.getClipBounds(); fBounds.setBounds(rect); paintHighlights(g, a); paintBorder(g, rect); if (clip != null) { g.clipRect(rect.x + leftInset, rect.y + topInset, rect.width - leftInset - rightInset, rect.height - topInset - bottomInset); } Container host = getContainer(); Image img = getImage(host == null || host.isEnabled()); if (img != null) { if (! hasPixels(img)) { // No pixels yet, use the default Icon icon = getLoadingImageIcon(); if (icon != null) { icon.paintIcon(host, g, rect.x + leftInset, rect.y + topInset); } } else { // Draw the image g.drawImage(img, rect.x + leftInset, rect.y + topInset, width, height, imageObserver); } } else { Icon icon = getNoImageIcon(); if (icon != null) { icon.paintIcon(host, g, rect.x + leftInset, rect.y + topInset); } View view = getAltView(); // Paint the view representing the alt text, if its non-null if (view != null && ((state & WIDTH_FLAG) == 0 || width > DEFAULT_WIDTH)) { // Assume layout along the y direction Rectangle altRect = new Rectangle (rect.x + leftInset + DEFAULT_WIDTH, rect.y + topInset, rect.width - leftInset - rightInset - DEFAULT_WIDTH, rect.height - topInset - bottomInset); view.paint(g, altRect); } } if (clip != null) { // Reset clip. g.setClip(clip.x, clip.y, clip.width, clip.height); } } private void paintHighlights(Graphics g, Shape shape) { if (container instanceof JTextComponent) { JTextComponent tc = (JTextComponent)container; Highlighter h = tc.getHighlighter(); if (h instanceof LayeredHighlighter) { ((LayeredHighlighter)h).paintLayeredHighlights (g, getStartOffset(), getEndOffset(), shape, tc, this); } } } private void paintBorder(Graphics g, Rectangle rect) { Color color = borderColor; if ((borderSize > 0 || image == null) && color != null) { int xOffset = leftInset - borderSize; int yOffset = topInset - borderSize; g.setColor(color); int n = (image == null) ? 1 : borderSize; for (int counter = 0; counter < n; counter++) { g.drawRect(rect.x + xOffset + counter, rect.y + yOffset + counter, rect.width - counter - counter - xOffset -xOffset-1, rect.height - counter - counter -yOffset-yOffset-1); } } } /** * Determines the preferred span for this view along an * axis. * * @param axis may be either X_AXIS or Y_AXIS * @return the span the view would like to be rendered into; * typically the view is told to render into the span * that is returned, although there is no guarantee; * the parent may choose to resize or break the view */ public float getPreferredSpan(int axis) { sync(); // If the attributes specified a width/height, always use it! if (axis == View.X_AXIS && (state & WIDTH_FLAG) == WIDTH_FLAG) { getPreferredSpanFromAltView(axis); return width + leftInset + rightInset; } if (axis == View.Y_AXIS && (state & HEIGHT_FLAG) == HEIGHT_FLAG) { getPreferredSpanFromAltView(axis); return height + topInset + bottomInset; } Image image = getImage(); if (image != null) { switch (axis) { case View.X_AXIS: return width + leftInset + rightInset; case View.Y_AXIS: return height + topInset + bottomInset; default: throw new IllegalArgumentException("Invalid axis: " + axis); } } else { View view = getAltView(); float retValue = 0f; if (view != null) { retValue = view.getPreferredSpan(axis); } switch (axis) { case View.X_AXIS: return retValue + (float)(width + leftInset + rightInset); case View.Y_AXIS: return retValue + (float)(height + topInset + bottomInset); default: throw new IllegalArgumentException("Invalid axis: " + axis); } } } /** * Determines the desired alignment for this view along an * axis. This is implemented to give the alignment to the * bottom of the icon along the y axis, and the default * along the x axis. * * @param axis may be either X_AXIS or Y_AXIS * @return the desired alignment; this should be a value * between 0.0 and 1.0 where 0 indicates alignment at the * origin and 1.0 indicates alignment to the full span * away from the origin; an alignment of 0.5 would be the * center of the view */ public float getAlignment(int axis) { switch (axis) { case View.Y_AXIS: return vAlign; default: return super.getAlignment(axis); } } /** * Provides a mapping from the document model coordinate space * to the coordinate space of the view mapped to it. * * @param pos the position to convert * @param a the allocated region to render into * @return the bounding box of the given position * @exception BadLocationException if the given position does not represent a * valid location in the associated document * @see View#modelToView */ public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException { int p0 = getStartOffset(); int p1 = getEndOffset(); if ((pos >= p0) && (pos <= p1)) { Rectangle r = a.getBounds(); if (pos == p1) { r.x += r.width; } r.width = 0; return r; } return null; } /** * Provides a mapping from the view coordinate space to the logical * coordinate space of the model. * * @param x the X coordinate * @param y the Y coordinate * @param a the allocated region to render into * @return the location within the model that best represents the * given point of view * @see View#viewToModel */ public int viewToModel(float x, float y, Shape a, Position.Bias[] bias) { Rectangle alloc = (Rectangle) a; if (x < alloc.x + alloc.width) { bias[0] = Position.Bias.Forward; return getStartOffset(); } bias[0] = Position.Bias.Backward; return getEndOffset(); } /** * Sets the size of the view. This should cause * layout of the view if it has any layout duties. * * @param width the width >= 0 * @param height the height >= 0 */ public void setSize(float width, float height) { sync(); if (getImage() == null) { View view = getAltView(); if (view != null) { view.setSize(Math.max(0f, width - (float)(DEFAULT_WIDTH + leftInset + rightInset)), Math.max(0f, height - (float)(topInset + bottomInset))); } } } /** * Returns true if this image within a link? */ private boolean isLink() { return ((state & LINK_FLAG) == LINK_FLAG); } /** * Returns true if the passed in image has a non-zero width and height. */ private boolean hasPixels(Image image) { return image != null && (image.getHeight(imageObserver) > 0) && (image.getWidth(imageObserver) > 0); } /** * Returns the preferred span of the View used to display the alt text, * or 0 if the view does not exist. */ private float getPreferredSpanFromAltView(int axis) { if (getImage() == null) { View view = getAltView(); if (view != null) { return view.getPreferredSpan(axis); } } return 0f; } /** * Request that this view be repainted. * Assumes the view is still at its last-drawn location. */ private void repaint(long delay) { if (container != null && fBounds != null) { container.repaint(delay, fBounds.x, fBounds.y, fBounds.width, fBounds.height); } } /** * Convenience method for getting an integer attribute from the elements * AttributeSet. */ private int getIntAttr(HTML.Attribute name, int deflt) { AttributeSet attr = getElement().getAttributes(); if (attr.isDefined(name)) { // does not check parents! int i; String val = (String)attr.getAttribute(name); if (val == null) { i = deflt; } else { try{ i = Math.max(0, Integer.parseInt(val)); }catch( NumberFormatException x ) { i = deflt; } } return i; } else return deflt; } /** * Makes sure the necessary properties and image is loaded. */ private void sync() { int s = state; if ((s & RELOAD_IMAGE_FLAG) != 0) { refreshImage(); } s = state; if ((s & RELOAD_FLAG) != 0) { synchronized(this) { state = (state | RELOAD_FLAG) ^ RELOAD_FLAG; } setPropertiesFromAttributes(); } } /** * Loads the image and updates the size accordingly. This should be * invoked instead of invoking <code>loadImage or * <code>updateImageSize directly. */ private void refreshImage() { synchronized(this) { // clear out width/height/realoadimage flag and set loading flag state = (state | LOADING_FLAG | RELOAD_IMAGE_FLAG | WIDTH_FLAG | HEIGHT_FLAG) ^ (WIDTH_FLAG | HEIGHT_FLAG | RELOAD_IMAGE_FLAG); image = null; width = height = 0; } try { // Load the image loadImage(); // And update the size params updateImageSize(); } finally { synchronized(this) { // Clear out state in case someone threw an exception. state = (state | LOADING_FLAG) ^ LOADING_FLAG; } } } /** * Loads the image from the URL <code>getImageURL. This should * only be invoked from <code>refreshImage. */ private void loadImage() { URL src = getImageURL(); Image newImage = null; if (src != null) { Dictionary cache = (Dictionary)getDocument(). getProperty(IMAGE_CACHE_PROPERTY); if (cache != null) { newImage = (Image)cache.get(src); } else { newImage = Toolkit.getDefaultToolkit().createImage(src); if (newImage != null && getLoadsSynchronously()) { // Force the image to be loaded by using an ImageIcon. ImageIcon ii = new ImageIcon(); ii.setImage(newImage); } } } image = newImage; } /** * Recreates and reloads the image. This should * only be invoked from <code>refreshImage. */ private void updateImageSize() { int newWidth = 0; int newHeight = 0; int newState = 0; Image newImage = getImage(); if (newImage != null) { Element elem = getElement(); AttributeSet attr = elem.getAttributes(); // Get the width/height and set the state ivar before calling // anything that might cause the image to be loaded, and thus the // ImageHandler to be called. newWidth = getIntAttr(HTML.Attribute.WIDTH, -1); if (newWidth > 0) { newState |= WIDTH_FLAG; } newHeight = getIntAttr(HTML.Attribute.HEIGHT, -1); if (newHeight > 0) { newState |= HEIGHT_FLAG; } if (newWidth <= 0) { newWidth = newImage.getWidth(imageObserver); if (newWidth <= 0) { newWidth = DEFAULT_WIDTH; } } if (newHeight <= 0) { newHeight = newImage.getHeight(imageObserver); if (newHeight <= 0) { newHeight = DEFAULT_HEIGHT; } } // Make sure the image starts loading: if ((newState & (WIDTH_FLAG | HEIGHT_FLAG)) != 0) { Toolkit.getDefaultToolkit().prepareImage(newImage, newWidth, newHeight, imageObserver); } else { Toolkit.getDefaultToolkit().prepareImage(newImage, -1, -1, imageObserver); } boolean createText = false; synchronized(this) { // If imageloading failed, other thread may have called // ImageLoader which will null out image, hence we check // for it. if (image != null) { if ((newState & WIDTH_FLAG) == WIDTH_FLAG || width == 0) { width = newWidth; } if ((newState & HEIGHT_FLAG) == HEIGHT_FLAG || height == 0) { height = newHeight; } } else { createText = true; if ((newState & WIDTH_FLAG) == WIDTH_FLAG) { width = newWidth; } if ((newState & HEIGHT_FLAG) == HEIGHT_FLAG) { height = newHeight; } } state = state | newState; state = (state | LOADING_FLAG) ^ LOADING_FLAG; } if (createText) { // Only reset if this thread determined image is null updateAltTextView(); } } else { width = height = DEFAULT_HEIGHT; updateAltTextView(); } } /** * Updates the view representing the alt text. */ private void updateAltTextView() { String text = getAltText(); if (text != null) { ImageLabelView newView; newView = new ImageLabelView(getElement(), text); synchronized(this) { altView = newView; } } } /** * Returns the view to use for alternate text. This may be null. */ private View getAltView() { View view; synchronized(this) { view = altView; } if (view != null && view.getParent() == null) { view.setParent(getParent()); } return view; } /** * Invokes <code>preferenceChanged on the event displatching * thread. */ private void safePreferenceChanged() { if (SwingUtilities.isEventDispatchThread()) { Document doc = getDocument(); if (doc instanceof AbstractDocument) { ((AbstractDocument)doc).readLock(); } preferenceChanged(null, true, true); if (doc instanceof AbstractDocument) { ((AbstractDocument)doc).readUnlock(); } } else { SwingUtilities.invokeLater(new Runnable() { public void run() { safePreferenceChanged(); } }); } } /** * ImageHandler implements the ImageObserver to correctly update the * display as new parts of the image become available. */ private class ImageHandler implements ImageObserver { // This can come on any thread. If we are in the process of reloading // the image and determining our state (loading == true) we don't fire // preference changed, or repaint, we just reset the fWidth/fHeight as // necessary and return. This is ok as we know when loading finishes // it will pick up the new height/width, if necessary. public boolean imageUpdate(Image img, int flags, int x, int y, int newWidth, int newHeight ) { if (img != image && img != disabledImage || image == null || getParent() == null) { return false; } // Bail out if there was an error: if ((flags & (ABORT|ERROR)) != 0) { repaint(0); synchronized(ImageView.this) { if (image == img) { // Be sure image hasn't changed since we don't // initialy synchronize image = null; if ((state & WIDTH_FLAG) != WIDTH_FLAG) { width = DEFAULT_WIDTH; } if ((state & HEIGHT_FLAG) != HEIGHT_FLAG) { height = DEFAULT_HEIGHT; } } else { disabledImage = null; } if ((state & LOADING_FLAG) == LOADING_FLAG) { // No need to resize or repaint, still in the process // of loading. return false; } } updateAltTextView(); safePreferenceChanged(); return false; } if (image == img) { // Resize image if necessary: short changed = 0; if ((flags & ImageObserver.HEIGHT) != 0 && !getElement(). getAttributes().isDefined(HTML.Attribute.HEIGHT)) { changed |= 1; } if ((flags & ImageObserver.WIDTH) != 0 && !getElement(). getAttributes().isDefined(HTML.Attribute.WIDTH)) { changed |= 2; } synchronized(ImageView.this) { if ((changed & 1) == 1 && (state & WIDTH_FLAG) == 0) { width = newWidth; } if ((changed & 2) == 2 && (state & HEIGHT_FLAG) == 0) { height = newHeight; } if ((state & LOADING_FLAG) == LOADING_FLAG) { // No need to resize or repaint, still in the process of // loading. return true; } } if (changed != 0) { // May need to resize myself, asynchronously: safePreferenceChanged(); return true; } } // Repaint when done or when new pixels arrive: if ((flags & (FRAMEBITS|ALLBITS)) != 0) { repaint(0); } else if ((flags & SOMEBITS) != 0 && sIsInc) { repaint(sIncRate); } return ((flags & ALLBITS) == 0); } } /** * ImageLabelView is used if the image can't be loaded, and * the attribute specified an alt attribute. It overriden a handle of * methods as the text is hardcoded and does not come from the document. */ private class ImageLabelView extends InlineView { private Segment segment; private Color fg; ImageLabelView(Element e, String text) { super(e); reset(text); } public void reset(String text) { segment = new Segment(text.toCharArray(), 0, text.length()); } public void paint(Graphics g, Shape a) { // Don't use supers paint, otherwise selection will be wrong // as our start/end offsets are fake. GlyphPainter painter = getGlyphPainter(); if (painter != null) { g.setColor(getForeground()); painter.paint(this, g, a, getStartOffset(), getEndOffset()); } } public Segment getText(int p0, int p1) { if (p0 < 0 || p1 > segment.array.length) { throw new RuntimeException("ImageLabelView: Stale view"); } segment.offset = p0; segment.count = p1 - p0; return segment; } public int getStartOffset() { return 0; } public int getEndOffset() { return segment.array.length; } public View breakView(int axis, int p0, float pos, float len) { // Don't allow a break return this; } public Color getForeground() { View parent; if (fg == null && (parent = getParent()) != null) { Document doc = getDocument(); AttributeSet attr = parent.getAttributes(); if (attr != null && (doc instanceof StyledDocument)) { fg = ((StyledDocument)doc).getForeground(attr); } } return fg; } } } Other Java examples (source code examples)Here is a short list of links related to this Java ImageView.java source code file: |
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