Improve the Android last resort font driver
* java/org/gnu/emacs/EmacsSdk7FontDriver.java (Sdk7Typeface): Rename fileName to familyName and cease attempting to infer a style from it. (EmacsSdk7FontDriver): Employ preset typefaces rather than enumerating each typeface within the system fonts directory. (draw): Circumvent kerning difficulties by advancing past each character individually.
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Po Lu
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1 changed files with 70 additions and 122 deletions
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@ -31,6 +31,19 @@
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import android.util.Log;
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/* EmacsSdk7FontDriver implements a fallback font driver under
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Android. This font driver is enabled when the SFNT font driver (in
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sfntfont-android.c) proves incapable of locating any fonts, which
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has hitherto not been observed in practice.
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This font driver does not supply each font installed on the system,
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in lieu of which it provides a list of fonts for each conceivable
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style and sub-type of the system's own Typefaces, which arises from
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Android's absence of suitable APIs for loading individual font
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files. */
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public class EmacsSdk7FontDriver extends EmacsFontDriver
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{
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private static final String TOFU_STRING = "\uDB3F\uDFFD";
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@ -46,106 +59,26 @@ protected static final class Sdk7Typeface
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public int slant, width, weight, spacing;
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public
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Sdk7Typeface (String fileName, Typeface typeface)
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Sdk7Typeface (String familyName, Typeface typeface)
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{
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String style, testString;
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int index, measured, i;
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float[] widths;
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/* Initialize the font style fields and create a paint object
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linked with that typeface. */
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slant = NORMAL;
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weight = REGULAR;
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width = UNSPECIFIED;
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spacing = PROPORTIONAL;
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this.typeface = typeface;
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this.familyName = familyName;
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typefacePaint = new Paint ();
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typefacePaint.setAntiAlias (true);
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typefacePaint.setTypeface (typeface);
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/* For the calls to measureText below. */
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typefacePaint.setTextSize (10.0f);
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/* Parse the file name into some useful data. First, strip off
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the extension. */
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fileName = fileName.split ("\\.", 2)[0];
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/* Next, split the file name by dashes. Everything before the
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last dash is part of the family name. */
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index = fileName.lastIndexOf ("-");
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if (index > 0)
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{
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style = fileName.substring (index + 1, fileName.length ());
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familyName = fileName.substring (0, index);
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/* Look for something describing the weight. */
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if (style.contains ("Thin"))
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weight = THIN;
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else if (style.contains ("UltraLight"))
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weight = ULTRA_LIGHT;
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else if (style.contains ("SemiLight"))
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weight = SEMI_LIGHT;
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else if (style.contains ("Light"))
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weight = LIGHT;
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else if (style.contains ("Medium"))
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weight = MEDIUM;
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else if (style.contains ("SemiBold"))
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weight = SEMI_BOLD;
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else if (style.contains ("ExtraBold"))
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weight = EXTRA_BOLD;
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else if (style.contains ("Bold"))
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weight = BOLD;
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else if (style.contains ("Black"))
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weight = BLACK;
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else if (style.contains ("UltraHeavy"))
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weight = ULTRA_HEAVY;
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/* And the slant. */
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if (style.contains ("ReverseOblique"))
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slant = OBLIQUE;
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else if (style.contains ("ReverseItalic"))
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slant = REVERSE_ITALIC;
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else if (style.contains ("Italic"))
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slant = ITALIC;
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else if (style.contains ("Oblique"))
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slant = OBLIQUE;
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/* Finally, the width. */
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if (style.contains ("UltraCondensed"))
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width = ULTRA_CONDENSED;
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else if (style.contains ("ExtraCondensed"))
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width = EXTRA_CONDENSED;
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else if (style.contains ("SemiCondensed"))
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width = SEMI_CONDENSED;
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else if (style.contains ("Condensed"))
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width = CONDENSED;
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else if (style.contains ("SemiExpanded"))
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width = SEMI_EXPANDED;
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else if (style.contains ("ExtraExpanded"))
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width = EXTRA_EXPANDED;
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else if (style.contains ("UltraExpanded"))
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width = ULTRA_EXPANDED;
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else if (style.contains ("Expanded"))
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width = EXPANDED;
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/* Guess the spacing information. */
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testString = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
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widths = new float[testString.length ()];
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measured = typefacePaint.getTextWidths (testString,
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0, testString.length (),
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widths);
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spacing = MONO;
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for (i = 0; i < measured; ++i)
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{
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if (i != 0 && widths[i - 1] != widths[i])
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/* This isn't a monospace font. */
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spacing = PROPORTIONAL;
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}
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}
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else
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familyName = fileName;
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}
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@Override
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@ -244,43 +177,42 @@ protected final class Sdk7FontObject extends FontObject
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EmacsSdk7FontDriver ()
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{
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int i;
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File systemFontsDirectory, fontFile;
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Typeface typeface;
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systemFontsDirectory = new File ("/system/fonts");
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typefaceList = new Sdk7Typeface[5];
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fontFamilyList = systemFontsDirectory.list ();
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/* Initialize the default monospace and Sans Serif typefaces.
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Initialize the same typeface with various distinct styles. */
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fallbackTypeface = new Sdk7Typeface ("Sans Serif",
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Typeface.DEFAULT);
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typefaceList[1] = fallbackTypeface;
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/* If that returned null, replace it with an empty array. */
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fontFamilyList = new String[0];
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fallbackTypeface = new Sdk7Typeface ("Sans Serif",
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Typeface.create (Typeface.DEFAULT,
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Typeface.BOLD));
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fallbackTypeface.weight = BOLD;
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typefaceList[2] = fallbackTypeface;
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typefaceList = new Sdk7Typeface[fontFamilyList.length + 3];
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fallbackTypeface = new Sdk7Typeface ("Sans Serif",
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Typeface.create (Typeface.DEFAULT,
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Typeface.ITALIC));
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fallbackTypeface.slant = ITALIC;
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typefaceList[3] = fallbackTypeface;
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/* It would be nice to avoid opening each and every font upon
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startup. But that doesn't seem to be possible on
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Android. */
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for (i = 0; i < fontFamilyList.length; ++i)
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{
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fontFile = new File (systemFontsDirectory,
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fontFamilyList[i]);
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typeface = Typeface.createFromFile (fontFile);
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typefaceList[i] = new Sdk7Typeface (fontFile.getName (),
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typeface);
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}
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/* Initialize the default monospace and serif typefaces. */
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fallbackTypeface = new Sdk7Typeface ("monospace",
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Typeface.MONOSPACE);
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typefaceList[fontFamilyList.length] = fallbackTypeface;
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fallbackTypeface
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= new Sdk7Typeface ("Sans Serif",
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Typeface.create (Typeface.DEFAULT,
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Typeface.BOLD_ITALIC));
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fallbackTypeface.weight = BOLD;
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fallbackTypeface.slant = ITALIC;
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typefaceList[4] = fallbackTypeface;
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fallbackTypeface = new Sdk7Typeface ("Monospace",
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Typeface.MONOSPACE);
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typefaceList[fontFamilyList.length + 1] = fallbackTypeface;
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fallbackTypeface.spacing = MONO;
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typefaceList[0] = fallbackTypeface;
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fallbackTypeface = new Sdk7Typeface ("Sans Serif",
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Typeface.DEFAULT);
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typefaceList[fontFamilyList.length + 2] = fallbackTypeface;
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fontFamilyList = new String[] { "Monospace", "Sans Serif", };
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}
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private boolean
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@ -491,16 +423,12 @@ else if (code.length == 1)
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{
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Rect backgroundRect, bounds;
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Sdk7FontObject sdk7FontObject;
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char[] charsArray;
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int i;
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Canvas canvas;
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Paint paint;
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char[] array;
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sdk7FontObject = (Sdk7FontObject) fontObject;
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charsArray = new char[chars.length];
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for (i = 0; i < chars.length; ++i)
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charsArray[i] = (char) chars[i];
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backgroundRect = new Rect ();
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backgroundRect.top = y - sdk7FontObject.ascent;
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@ -526,13 +454,33 @@ else if (code.length == 1)
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paint.setTextSize (sdk7FontObject.pixelSize);
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paint.setTypeface (sdk7FontObject.typeface.typeface);
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paint.setAntiAlias (true);
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canvas.drawText (charsArray, 0, chars.length, x, y, paint);
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/* Android applies kerning to non-monospaced fonts by default,
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which brings the dimensions of strings drawn via `drawText' out
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of agreement with measurements previously provided to redisplay
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by textExtents. To avert such disaster, draw each character
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individually, advancing the origin point by hand. */
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bounds = new Rect ();
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paint.getTextBounds (charsArray, 0, chars.length, bounds);
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bounds.offset (x, y);
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bounds.union (backgroundRect);
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drawable.damageRect (bounds);
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array = new char[1];
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for (i = 0; i < chars.length; ++i)
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{
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/* Retrieve the text bounds for this character so as to
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compute the damage rectangle. */
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array[0] = (char) chars[i];
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paint.getTextBounds (array, 0, 1, bounds);
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bounds.offset (x, y);
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backgroundRect.union (bounds);
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/* Draw this character. */
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canvas.drawText (array, 0, 1, x, y, paint);
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/* Advance the origin point by that much. */
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x += paint.measureText ("" + array[0]);
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}
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drawable.damageRect (backgroundRect);
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paint.setAntiAlias (false);
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return 1;
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}
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