GTK: Step 1 of tab strip refresh.

ui/gfx/canvas_skia_linux.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/canvas_skia.h"
 
 #include <algorithm>
 
 #include <cairo/cairo.h>
 #include <pango/pango.h>
 #include <pango/pangocairo.h>
 
 #include "base/i18n/rtl.h"
 #include "base/logging.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/pango_util.h"
 #include "ui/gfx/platform_font_pango.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/skia_util.h"
 
 #if defined(TOOLKIT_USES_GTK)
 #include <gdk/gdk.h>
 #endif
 
 using std::max;
 
 namespace {
 
-// Multiply by the text height to determine how much text should be faded
-// when elliding.
-const double kFadeWidthFactor = 1.5;
-
-// End state of the elliding fade.
-const double kFadeFinalAlpha = 0.15;
-
 // Width of the border drawn around haloed text.
 const double kTextHaloWidth = 1.0;
 
 // A class to encapsulate string drawing params and operations.
-class DrawStringContext {
+class DrawStringContext : public gfx::PangoDrawString {
  public:
   DrawStringContext(gfx::CanvasSkia* canvas,
                     const string16& text,
                     const gfx::Font& font,
                     const gfx::Rect& bounds,
                     const gfx::Rect& clip,
                     int flags);
   ~DrawStringContext();
 
-  void Draw(const SkColor& text_color);
   void DrawWithHalo(const SkColor& text_color, const SkColor& halo_color);
 
  private:
-  // Draw an underline under the text using |cr|, which must already be
-  // initialized with the correct source.  |extra_edge_width| is added to the
-  // outer edge of the line.  Helper method for Draw() and DrawWithHalo().
-  void DrawUnderline(cairo_t* cr, double extra_edge_width);
-
-  const gfx::Rect& bounds_;
-  int flags_;
-  const gfx::Font& font_;
-
   gfx::CanvasSkia* canvas_;
-  cairo_t* cr_;
-  PangoLayout* layout_;
-
-  int text_x_;
-  int text_y_;
-  int text_width_;
-  int text_height_;
-
-  base::i18n::TextDirection text_direction_;
 
   DISALLOW_COPY_AND_ASSIGN(DrawStringContext);
 };
 
 DrawStringContext::DrawStringContext(gfx::CanvasSkia* canvas,
                                      const string16& text,
                                      const gfx::Font& font,
                                      const gfx::Rect& bounds,
                                      const gfx::Rect& clip,
                                      int flags)
-    : bounds_(bounds),
-      flags_(flags),
-      font_(font),
-      canvas_(canvas),
-      cr_(NULL),
-      layout_(NULL),
-      text_x_(bounds.x()),
-      text_y_(bounds.y()),
-      text_width_(0),
-      text_height_(0),
-      text_direction_(base::i18n::GetFirstStrongCharacterDirection(text)) {
-  DCHECK(!bounds_.IsEmpty());
-
-  cr_ = skia::BeginPlatformPaint(canvas_->sk_canvas());
-  layout_ = pango_cairo_create_layout(cr_);
-
-  gfx::SetupPangoLayout(
-      layout_, text, font, bounds_.width(), text_direction_, flags_);
-
-  pango_layout_set_height(layout_, bounds_.height() * PANGO_SCALE);
-
-  cairo_save(cr_);
-
-  cairo_rectangle(cr_, clip.x(), clip.y(), clip.width(), clip.height());
-  cairo_clip(cr_);
-
-  pango_layout_get_pixel_size(layout_, &text_width_, &text_height_);
-
-  if (flags_ & gfx::Canvas::TEXT_VALIGN_TOP) {
-    // Cairo should draw from the top left corner already.
-  } else if (flags_ & gfx::Canvas::TEXT_VALIGN_BOTTOM) {
-    text_y_ += (bounds.height() - text_height_);
-  } else {
-    // Vertically centered.
-    text_y_ += ((bounds.height() - text_height_) / 2);
-  }
+    : PangoDrawString(skia::BeginPlatformPaint(canvas->sk_canvas()),
+                      text,
+                      font,
+                      bounds,
+                      clip,
+                      flags),
+      canvas_(canvas) {
 }
 
 DrawStringContext::~DrawStringContext() {
-  cairo_restore(cr_);
   skia::EndPlatformPaint(canvas_->sk_canvas());
-  g_object_unref(layout_);
-  // NOTE: BeginPlatformPaint returned its surface, we shouldn't destroy it.
-}
-
-void DrawStringContext::Draw(const SkColor& text_color) {
-  double r = SkColorGetR(text_color) / 255.0,
-         g = SkColorGetG(text_color) / 255.0,
-         b = SkColorGetB(text_color) / 255.0,
-         a = SkColorGetA(text_color) / 255.0;
-
-  cairo_pattern_t* pattern = NULL;
-
-  cairo_save(cr_);
-
-  // If we're not eliding, use a fixed color.
-  // Otherwise, create a gradient pattern to use as the source.
-  if (text_direction_ == base::i18n::RIGHT_TO_LEFT ||
-      (flags_ & gfx::Canvas::NO_ELLIPSIS) ||
-      text_width_ <= bounds_.width()) {
-    cairo_set_source_rgba(cr_, r, g, b, a);
-  } else {
-    // Fade to semi-transparent to elide.
-    int fade_width = static_cast<double>(text_height_) * kFadeWidthFactor;
-    if (fade_width > (bounds_.width() / 2)) {
-      // Don't fade more than half the text.
-      fade_width = bounds_.width() / 2;
-    }
-    int fade_x = bounds_.x() + bounds_.width() - fade_width;
-
-    pattern = cairo_pattern_create_linear(
-        fade_x, bounds_.y(), bounds_.x() + bounds_.width(), bounds_.y());
-    cairo_pattern_add_color_stop_rgba(pattern, 0, r, g, b, a);
-    cairo_pattern_add_color_stop_rgba(pattern, 1, r, g, b, kFadeFinalAlpha);
-    cairo_set_source(cr_, pattern);
-  }
-
-  cairo_move_to(cr_, text_x_, text_y_);
-  pango_cairo_show_layout(cr_, layout_);
-
-  if (font_.GetStyle() & gfx::Font::UNDERLINED)
-    DrawUnderline(cr_, 0.0);
-
-  if (pattern)
-    cairo_pattern_destroy(pattern);
-
-  cairo_restore(cr_);
 }
 
 void DrawStringContext::DrawWithHalo(const SkColor& text_color,
                                      const SkColor& halo_color) {
   gfx::CanvasSkia text_canvas(bounds_.width() + 2, bounds_.height() + 2, false);
   text_canvas.FillRectInt(static_cast<SkColor>(0),
       0, 0, bounds_.width() + 2, bounds_.height() + 2);
 
   {
     skia::ScopedPlatformPaint scoped_platform_paint(text_canvas.sk_canvas());
@@ skipping 33 matching lines @@
 
     if (font_.GetStyle() & gfx::Font::UNDERLINED)
       DrawUnderline(text_cr, 0.0);
   }
 
   const SkBitmap& text_bitmap = const_cast<SkBitmap&>(
       skia::GetTopDevice(*text_canvas.sk_canvas())->accessBitmap(false));
   canvas_->DrawBitmapInt(text_bitmap, text_x_ - 1, text_y_ - 1);
 }
 
-void DrawStringContext::DrawUnderline(cairo_t* cr, double extra_edge_width) {
-  gfx::PlatformFontPango* platform_font =
-      static_cast<gfx::PlatformFontPango*>(font_.platform_font());
-  const double underline_y =
-      static_cast<double>(text_y_) + text_height_ +
-      platform_font->underline_position();
-  cairo_set_line_width(
-      cr, platform_font->underline_thickness() + 2 * extra_edge_width);
-  cairo_move_to(cr, text_x_ - extra_edge_width, underline_y);
-  cairo_line_to(cr, text_x_ + text_width_ + extra_edge_width, underline_y);
-  cairo_stroke(cr);
-}
-
 }  // namespace
 
 namespace gfx {
 
 // static
 void CanvasSkia::SizeStringInt(const string16& text,
                                const gfx::Font& font,
                                int* width, int* height,
                                int flags) {
   int org_width = *width;
@@ skipping 88 matching lines @@
   cairo_paint(cr);
 }
 #endif  // defined(TOOLKIT_USES_GTK)
 
 ui::TextureID CanvasSkia::GetTextureID() {
   // TODO(wjmaclean)
   return 0;
 }
 
 }  // namespace gfx