diff options
Diffstat (limited to 'libjava/classpath/javax/swing/plaf/basic/BasicGraphicsUtils.java')
| -rw-r--r-- | libjava/classpath/javax/swing/plaf/basic/BasicGraphicsUtils.java | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/libjava/classpath/javax/swing/plaf/basic/BasicGraphicsUtils.java b/libjava/classpath/javax/swing/plaf/basic/BasicGraphicsUtils.java index 068de345bec..1e84be93282 100644 --- a/libjava/classpath/javax/swing/plaf/basic/BasicGraphicsUtils.java +++ b/libjava/classpath/javax/swing/plaf/basic/BasicGraphicsUtils.java @@ -37,6 +37,8 @@ exception statement from your version. */ package javax.swing.plaf.basic; +import gnu.classpath.SystemProperties; + import java.awt.Color; import java.awt.Dimension; import java.awt.Font; @@ -65,6 +67,14 @@ import javax.swing.SwingUtilities; public class BasicGraphicsUtils { /** + * Used as a key for a client property to store cached TextLayouts in. This + * is used for speed-up drawing of text in + * {@link #drawString(Graphics, String, int, int, int)}. + */ + static final String CACHED_TEXT_LAYOUT = + "BasicGraphicsUtils.cachedTextLayout"; + + /** * Constructor. It is utterly unclear why this class should * be constructable, but this is what the API specification * says. @@ -536,6 +546,170 @@ public class BasicGraphicsUtils g2.fill(underline); } + /** + * Draws a string on the specified component. + * + * @param c the component + * @param g the Graphics context + * @param text the string + * @param underlinedChar the character to be underlined + * @param x the X location + * @param y the Y location + */ + static void drawString(JComponent c, Graphics g, String text, + int underlinedChar, int x, int y) + { + int index = -1; + + /* It is intentional that lower case is used. In some languages, + * the set of lowercase characters is larger than the set of + * uppercase ones. Therefore, it is good practice to use lowercase + * for such comparisons (which really means that the author of this + * code can vaguely remember having read some Unicode techreport + * with this recommendation, but is too lazy to look for the URL). + */ + if ((underlinedChar >= 0) || (underlinedChar <= 0xffff)) + index = text.toLowerCase().indexOf( + Character.toLowerCase((char) underlinedChar)); + + drawStringUnderlineCharAt(c, g, text, index, x, y); + } + + + /** + * Draws a String at the given location, underlining the character + * at the specified index. Drawing is performed in the current color + * and font of <code>g</code>. + * + * <p><img src="doc-files/BasicGraphicsUtils-5.png" width="500" + * height="100" alt="[An illustration showing how to use the + * method]" /> + * + * This is an accelerated version of the method with the same name. It + * uses a pre-laid out TextLayout stored in a client property. + * + * @param c the component that is drawn + * @param g the graphics into which the String is drawn. + * + * @param text the String to draw. + * + * @param underlinedIndex the index of the underlined character in + * <code>text</code>. If <code>underlinedIndex</code> falls + * outside the range <code>[0, text.length() - 1]</code>, the + * text will be drawn without underlining anything. + * + * @param x the x coordinate of the text, as it would be passed to + * {@link java.awt.Graphics#drawString(java.lang.String, + * int, int)}. + * + * @param y the y coordinate of the text, as it would be passed to + * {@link java.awt.Graphics#drawString(java.lang.String, + * int, int)}. + */ + static void drawStringUnderlineCharAt(JComponent c, Graphics g, String text, + int underlinedIndex, + int x, int y) + { + Graphics2D g2; + Rectangle2D.Double underline; + FontRenderContext frc; + FontMetrics fmet; + LineMetrics lineMetrics; + Font font; + TextLayout layout; + double underlineX1, underlineX2; + boolean drawUnderline; + int textLength; + + textLength = text.length(); + if (textLength == 0) + return; + + drawUnderline = (underlinedIndex >= 0) && (underlinedIndex < textLength); + + // FIXME: unfortunately pango and cairo can't agree on metrics + // so for the time being we continue to *not* use TextLayouts. + if (!(g instanceof Graphics2D) + || SystemProperties.getProperty("gnu.javax.swing.noGraphics2D") != null) + { + /* Fall-back. This is likely to produce garbage for any text + * containing right-to-left (Hebrew or Arabic) characters, even + * if the underlined character is left-to-right. + */ + g.drawString(text, x, y); + if (drawUnderline) + { + fmet = g.getFontMetrics(); + g.fillRect( + /* x */ x + fmet.stringWidth(text.substring(0, underlinedIndex)), + /* y */ y + fmet.getDescent() - 1, + /* width */ fmet.charWidth(text.charAt(underlinedIndex)), + /* height */ 1); + } + + return; + } + + g2 = (Graphics2D) g; + font = g2.getFont(); + frc = g2.getFontRenderContext(); + lineMetrics = font.getLineMetrics(text, frc); + layout = (TextLayout) c.getClientProperty(CACHED_TEXT_LAYOUT); + if (layout == null) + { + layout = new TextLayout(text, font, frc); + System.err.println("Unable to use cached TextLayout for: " + text); + } + + /* Draw the text. */ + layout.draw(g2, x, y); + if (!drawUnderline) + return; + + underlineX1 = x + layout.getLogicalHighlightShape( + underlinedIndex, underlinedIndex).getBounds2D().getX(); + underlineX2 = x + layout.getLogicalHighlightShape( + underlinedIndex + 1, underlinedIndex + 1).getBounds2D().getX(); + + underline = new Rectangle2D.Double(); + if (underlineX1 < underlineX2) + { + underline.x = underlineX1; + underline.width = underlineX2 - underlineX1; + } + else + { + underline.x = underlineX2; + underline.width = underlineX1 - underlineX2; + } + + + underline.height = lineMetrics.getUnderlineThickness(); + underline.y = lineMetrics.getUnderlineOffset(); + if (underline.y == 0) + { + /* Some fonts do not specify an underline offset, although they + * actually should do so. In that case, the result of calling + * lineMetrics.getUnderlineOffset() will be zero. Since it would + * look very ugly if the underline was be positioned immediately + * below the baseline, we check for this and move the underline + * below the descent, as shown in the following ASCII picture: + * + * ##### ##### # + * # # # # + * # # # # + * # # # # + * ##### ###### ---- baseline (0) + * # + * # + * ------------------###----------- lineMetrics.getDescent() + */ + underline.y = lineMetrics.getDescent(); + } + + underline.y += y; + g2.fill(underline); + } /** * Draws a rectangle, simulating a dotted stroke by painting only |
