1 files changed, 99 insertions, 0 deletions
diff --git a/WebCore/platform/graphics/cairo/DrawErrorUnderline.h b/WebCore/platform/graphics/cairo/DrawErrorUnderline.h
new file mode 100644
index 0000000..9776853
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+++ b/WebCore/platform/graphics/cairo/DrawErrorUnderline.h
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+/*
+ * Copyright (C) 2004 Red Hat, Inc.
+ * Copyright (C) 2010 Brent Fulgham <bfulgham@webkit.org>
+ *
+ * Based on Pango sources (see pangocairo-render.c)
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ */
+
+#if PLATFORM(CAIRO)
+
+#include <cairo.h>
+
+//
+// Draws an error underline that looks like one of:
+//
+//              H       E                H
+//     /\      /\      /\        /\      /\               -
+//   A/  \    /  \    /  \     A/  \    /  \              |
+//    \   \  /    \  /   /D     \   \  /    \             |
+//     \   \/  C   \/   /        \   \/   C  \            | height = heightSquares * square
+//      \      /\  F   /          \  F   /\   \           |
+//       \    /  \    /            \    /  \   \G         |
+//        \  /    \  /              \  /    \  /          |
+//         \/      \/                \/      \/           -
+//         B                         B
+//         |---|
+//       unitWidth = (heightSquares - 1) * square
+//
+// The x, y, width, height passed in give the desired bounding box;
+// x/width are adjusted to make the underline a integer number of units
+// wide.
+//
+static inline void drawErrorUnderline(cairo_t* cr, double x, double y, double width, double height)
+{
+    static const double heightSquares = 2.5;
+
+    double square = height / heightSquares;
+    double halfSquare = 0.5 * square;
+
+    double unitWidth = (heightSquares - 1.0) * square;
+    int widthUnits = static_cast<int>(0.5 * (width + unitWidth) / unitWidth);
+
+    x += 0.5 * (width - widthUnits * unitWidth);
+    width = widthUnits * unitWidth;
+
+    double bottom = y + height;
+    double top = y;
+
+    // Bottom of squiggle
+    cairo_move_to(cr, x - halfSquare, top + halfSquare); // A
+
+    int i = 0;
+    for (i = 0; i < widthUnits; i += 2) {
+        double middle = x + (i + 1) * unitWidth;
+        double right = x + (i + 2) * unitWidth;
+
+        cairo_line_to(cr, middle, bottom); // B
+
+        if (i + 2 == widthUnits)
+            cairo_line_to(cr, right + halfSquare, top + halfSquare); // D
+        else if (i + 1 != widthUnits)
+            cairo_line_to(cr, right, top + square); // C
+    }
+
+    // Top of squiggle
+    for (i -= 2; i >= 0; i -= 2) {
+        double left = x + i * unitWidth;
+        double middle = x + (i + 1) * unitWidth;
+        double right = x + (i + 2) * unitWidth;
+
+        if (i + 1 == widthUnits)
+            cairo_line_to(cr, middle + halfSquare, bottom - halfSquare); // G
+        else {
+            if (i + 2 == widthUnits)
+                cairo_line_to(cr, right, top); // E
+
+            cairo_line_to(cr, middle, bottom - halfSquare); // F
+        }
+
+        cairo_line_to(cr, left, top); // H
+    }
+}
+
+#endif