Implement Pango RenderText for Linux.

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 <gtk/gtk.h>
 #include <pango/pango.h>
 #include <pango/pangocairo.h>
 
 #include "base/i18n/rtl.h"
 #include "base/logging.h"
-#include "base/utf_string_conversions.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/gtk_util.h"
+#include "ui/gfx/pango_util.h"
 #include "ui/gfx/platform_font_gtk.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/skia_util.h"
 
 using std::max;
 
 namespace {
 
-const gunichar kAcceleratorChar = '&';
-
 // 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;
 
-// Font settings that we initialize once and then use when drawing text in
-// DrawStringInt().
-cairo_font_options_t* cairo_font_options = NULL;
-
-// Update |cairo_font_options| based on GtkSettings, allocating it if needed.
-void UpdateCairoFontOptions() {
-  if (!cairo_font_options)
-    cairo_font_options = cairo_font_options_create();
-
-  gint antialias = 0;
-  gint hinting = 0;
-  gchar* hint_style = NULL;
-  gchar* rgba_style = NULL;
-
-#if !defined(USE_WAYLAND)
-  GtkSettings* gtk_settings = gtk_settings_get_default();
-  g_object_get(gtk_settings,
-               "gtk-xft-antialias", &antialias,
-               "gtk-xft-hinting", &hinting,
-               "gtk-xft-hintstyle", &hint_style,
-               "gtk-xft-rgba", &rgba_style,
-               NULL);
-#endif
-
-  // g_object_get() doesn't tell us whether the properties were present or not,
-  // but if they aren't (because gnome-settings-daemon isn't running), we'll get
-  // NULL values for the strings.
-  if (hint_style && rgba_style) {
-    if (!antialias) {
-      cairo_font_options_set_antialias(cairo_font_options,
-                                       CAIRO_ANTIALIAS_NONE);
-    } else if (strcmp(rgba_style, "none") == 0) {
-      cairo_font_options_set_antialias(cairo_font_options,
-                                       CAIRO_ANTIALIAS_GRAY);
-    } else {
-      cairo_font_options_set_antialias(cairo_font_options,
-                                       CAIRO_ANTIALIAS_SUBPIXEL);
-      cairo_subpixel_order_t cairo_subpixel_order =
-          CAIRO_SUBPIXEL_ORDER_DEFAULT;
-      if (strcmp(rgba_style, "rgb") == 0) {
-        cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_RGB;
-      } else if (strcmp(rgba_style, "bgr") == 0) {
-        cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_BGR;
-      } else if (strcmp(rgba_style, "vrgb") == 0) {
-        cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_VRGB;
-      } else if (strcmp(rgba_style, "vbgr") == 0) {
-        cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_VBGR;
-      }
-      cairo_font_options_set_subpixel_order(cairo_font_options,
-                                            cairo_subpixel_order);
-    }
-
-    cairo_hint_style_t cairo_hint_style = CAIRO_HINT_STYLE_DEFAULT;
-    if (hinting == 0 || strcmp(hint_style, "hintnone") == 0) {
-      cairo_hint_style = CAIRO_HINT_STYLE_NONE;
-    } else if (strcmp(hint_style, "hintslight") == 0) {
-      cairo_hint_style = CAIRO_HINT_STYLE_SLIGHT;
-    } else if (strcmp(hint_style, "hintmedium") == 0) {
-      cairo_hint_style = CAIRO_HINT_STYLE_MEDIUM;
-    } else if (strcmp(hint_style, "hintfull") == 0) {
-      cairo_hint_style = CAIRO_HINT_STYLE_FULL;
-    }
-    cairo_font_options_set_hint_style(cairo_font_options, cairo_hint_style);
-  }
-
-  if (hint_style)
-    g_free(hint_style);
-  if (rgba_style)
-    g_free(rgba_style);
-}
-
-// Pass a width > 0 to force wrapping and elliding.
-void SetupPangoLayout(PangoLayout* layout,
-                      const string16& text,
-                      const gfx::Font& font,
-                      int width,
-                      base::i18n::TextDirection text_direction,
-                      int flags) {
-  if (!cairo_font_options)
-    UpdateCairoFontOptions();
-  // This needs to be done early on; it has no effect when called just before
-  // pango_cairo_show_layout().
-  pango_cairo_context_set_font_options(
-      pango_layout_get_context(layout), cairo_font_options);
-
-  // Callers of DrawStringInt handle RTL layout themselves, so tell pango to not
-  // scope out RTL characters.
-  pango_layout_set_auto_dir(layout, FALSE);
-
-  if (width > 0)
-    pango_layout_set_width(layout, width * PANGO_SCALE);
-
-  if (flags & gfx::Canvas::TEXT_ALIGN_CENTER) {
-    // We don't support center aligned w/ eliding.
-    DCHECK(gfx::Canvas::NO_ELLIPSIS);
-    pango_layout_set_alignment(layout, PANGO_ALIGN_CENTER);
-  } else if (flags & gfx::Canvas::TEXT_ALIGN_RIGHT) {
-    pango_layout_set_alignment(layout, PANGO_ALIGN_RIGHT);
-  }
-
-  if (flags & gfx::Canvas::NO_ELLIPSIS) {
-    pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_NONE);
-    if (flags & gfx::Canvas::MULTI_LINE) {
-      pango_layout_set_wrap(layout,
-          (flags & gfx::Canvas::CHARACTER_BREAK) ?
-              PANGO_WRAP_WORD_CHAR : PANGO_WRAP_WORD);
-    }
-  } else if (text_direction == base::i18n::RIGHT_TO_LEFT){
-    pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_END);
-  } else {
-    // Fading the text will be handled in the draw operation.
-    // that the text is only on one line.
-    pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_NONE);
-    pango_layout_set_width(layout, -1);
-  }
-
-  // Set the resolution to match that used by Gtk. If we don't set the
-  // resolution and the resolution differs from the default, Gtk and Chrome end
-  // up drawing at different sizes.
-  double resolution = gfx::GetPangoResolution();
-  if (resolution > 0) {
-    pango_cairo_context_set_resolution(pango_layout_get_context(layout),
-                                       resolution);
-  }
-
-  PangoFontDescription* desc = font.GetNativeFont();
-  pango_layout_set_font_description(layout, desc);
-  pango_font_description_free(desc);
-
-  // Set text and accelerator character if needed.
-  std::string utf8 = UTF16ToUTF8(text);
-  if (flags & gfx::Canvas::SHOW_PREFIX) {
-    // Escape the text string to be used as markup.
-    gchar* escaped_text = g_markup_escape_text(utf8.c_str(), utf8.size());
-    pango_layout_set_markup_with_accel(layout,
-                                       escaped_text,
-                                       strlen(escaped_text),
-                                       kAcceleratorChar, NULL);
-    g_free(escaped_text);
-  } else if (flags & gfx::Canvas::HIDE_PREFIX) {
-    // Remove the ampersand character.  A double ampersand is output as
-    // a single ampersand.
-    DCHECK_EQ(1, g_unichar_to_utf8(kAcceleratorChar, NULL));
-    const std::string accelerator_removed =
-        gfx::RemoveAcceleratorChar(utf8, static_cast<char>(kAcceleratorChar));
-
-    pango_layout_set_text(layout,
-        accelerator_removed.data(), accelerator_removed.size());
-  } else {
-    pango_layout_set_text(layout, utf8.data(), utf8.size());
-  }
-}
-
 // A class to encapsulate string drawing params and operations.
 class DrawStringContext {
  public:
   DrawStringContext(gfx::CanvasSkia* canvas,
                     const string16& text,
                     const gfx::Font& font,
                     const gfx::Rect& bounds,
                     const gfx::Rect& clip,
                     int flags);
   ~DrawStringContext();
@@ skipping 40 matching lines @@
       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_);
   layout_ = pango_cairo_create_layout(cr_);
 
-  SetupPangoLayout(
+  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_);
@@ skipping 232 matching lines @@
   gdk_cairo_set_source_pixbuf(cr, pixbuf, x, y);
   cairo_paint(cr);
 }
 
 ui::TextureID CanvasSkia::GetTextureID() {
   // TODO(wjmaclean)
   return 0;
 }
 
 }  // namespace gfx