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>
@@ skipping 89 matching lines @@
     }
     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);

[msw, 2011/08/19 23:16:59]

You removed this line amidst the function move, any reason?

[xji, 2011/08/22 23:57:28]

The condition checking was changed from base:i18n:isRTL() to text_direction in
r91881
http://src.chromium.org/viewvc/chrome/trunk/src/ui/gfx/canvas_skia_linux.cc?r...

I thought it was setting it wrong and I changed it to use base:i18n:isRTL()
again. (if you look down after this code in the removed code, you will see the
width is set as -1 when base:i18n:isRTL().

But reading r91881 and r87431 again, I think I probably was wrong.

without setting pango layout width, I changed the code to use ViewPort to
TextPort conversion you added in RenderTextWin (thanks!)

I put the 2 conversion functions in RenderText. To be more accurately, I should
use layout's alignment (instead of base:i18n::isRTL), but since we align right
only when isRTL() is true and I think it is less likely to change. It should be
ok to have the 2 functions as common API.

-  }
-
-  // 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 120 matching lines @@
       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 {
 
+// Pass a width > 0 to force wrapping and elliding.
+void SetupPangoLayout(PangoLayout* layout,
+                      const string16& text,
+                      const 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 & 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 & Canvas::TEXT_ALIGN_RIGHT) {
+    pango_layout_set_alignment(layout, PANGO_ALIGN_RIGHT);
+  }
+
+  if (flags & Canvas::NO_ELLIPSIS) {
+    pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_NONE);
+    if (flags & Canvas::MULTI_LINE) {
+      pango_layout_set_wrap(layout,
+          (flags & 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.

[msw, 2011/08/19 23:16:59]

Can you clarify (or at least complete) the second comment sentence here?

[xji, 2011/08/22 23:57:28]

the comments was added by davemoore in
http://codereview.chromium.org/7105001/diff/1/ui/gfx/canvas_skia_linux.cc.
Checked with him and changed the comment as "Ensure that the text...."

+    pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_NONE);
+  }
+
+  if (!base::i18n::IsRTL())
+    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 = 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 & 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 & 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 =
+        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());
+  }
+}
+
 CanvasSkia::CanvasSkia(int width, int height, bool is_opaque)
     : skia::PlatformCanvas(width, height, is_opaque) {
 }
 
 CanvasSkia::CanvasSkia() : skia::PlatformCanvas() {
 }
 
 CanvasSkia::~CanvasSkia() {
 }
 
@@ skipping 92 matching lines @@
   gdk_cairo_set_source_pixbuf(cr, pixbuf, x, y);
   cairo_paint(cr);
 }
 
 ui::TextureID CanvasSkia::GetTextureID() {
   // TODO(wjmaclean)
   return 0;
 }
 
 }  // namespace gfx