VR: Avoiding regeneration of RenderText objects for texture rendering

chrome/browser/android/vr_shell/textures/url_bar_texture.cc

 // Copyright 2017 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 "chrome/browser/android/vr_shell/textures/url_bar_texture.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "cc/paint/skia_paint_canvas.h"
 #include "components/security_state/core/security_state.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/font_list.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/paint_vector_icon.h"
+#include "ui/gfx/render_text.h"
 #include "ui/gfx/vector_icon_types.h"
 #include "ui/vector_icons/vector_icons.h"
 
 namespace vr_shell {
 
 namespace {
 
-static constexpr SkColor kTextureBackground = 0x00AAAAAA;
 static constexpr SkColor kBackground = 0xCCAAAAAA;
 static constexpr SkColor kBackgroundHover = 0xCCDDDDDD;
 static constexpr SkColor kForeground = 0xCC444444;
 static constexpr SkColor kSeparatorColor =
     SkColorSetARGBMacro(256 * 0.2, 0, 0, 0);
 
 static constexpr float kWidth = 0.672;
 static constexpr float kHeight = 0.088;
 static constexpr float kFontHeight = 0.027;
 static constexpr float kBackButtonWidth = kHeight;
@@ skipping 48 matching lines @@
   size_.set_height(texture_size.height());
   size_.set_width(texture_size.width());
 
   canvas->save();
   canvas->scale(size_.width() / kWidth, size_.width() / kWidth);
 
   // Make a gfx canvas to support utility drawing methods.
   cc::SkiaPaintCanvas paint_canvas(canvas);
   gfx::Canvas gfx_canvas(&paint_canvas, 1.0f);
 
-  canvas->drawColor(kTextureBackground);
-
   // Back button area.
   SkRRect round_rect;
   SkVector rounded_corner = {kHeight / 2, kHeight / 2};
   SkVector left_corners[4] = {rounded_corner, {0, 0}, {0, 0}, rounded_corner};
   round_rect.setRectRadii({0, 0, kHeight, kHeight}, left_corners);
   SkPaint paint;
   paint.setColor(hover_ ? kBackgroundHover : kBackground);
   canvas->drawRRect(round_rect, paint);
 
   // URL area.
@@ skipping 11 matching lines @@
   canvas->save();
   canvas->translate(kHeight / 2 + kBackIconOffset, kHeight / 2);
   canvas->translate(-kBackIconHeight / 2, -kBackIconHeight / 2);
   int icon_default_height = GetDefaultSizeOfVectorIcon(ui::kBackArrowIcon);
   float icon_scale = kBackIconHeight / icon_default_height;
   canvas->scale(icon_scale, icon_scale);
   PaintVectorIcon(&gfx_canvas, ui::kBackArrowIcon, kForeground);
   canvas->restore();
 
   // Site security state icon.
-  // TODO(cjgrant): Plug in the correct icons based on security level.
-  if (!gurl_.spec().empty()) {
+  if (!gurl_.is_empty()) {
     canvas->save();
     canvas->translate(
         kBackButtonWidth + kSeparatorWidth + kSecurityFieldWidth / 2,
         kHeight / 2);
     canvas->translate(-kSecurityIconHeight / 2, -kSecurityIconHeight / 2);
     const gfx::VectorIcon& security_icon = getSecurityIcon(security_level_);
     icon_default_height = GetDefaultSizeOfVectorIcon(security_icon);
     icon_scale = kSecurityIconHeight / icon_default_height;
     canvas->scale(icon_scale, icon_scale);
     PaintVectorIcon(&gfx_canvas, security_icon, kForeground);
     canvas->restore();
   }
 
   canvas->restore();
 
-  // Draw text based on pixel sizes rather than meters, for correct font sizing.
-  int pixel_font_height = texture_size.height() * kFontHeight / kHeight;
-  int text_flags = gfx::Canvas::TEXT_ALIGN_LEFT;
-  float url_x = kBackButtonWidth + kSeparatorWidth + kSecurityFieldWidth;
-  float url_width = kWidth - url_x - kUrlRightMargin;
-  gfx_canvas.DrawStringRectWithFlags(
-      base::UTF8ToUTF16(gurl_.spec()), GetDefaultFontList(pixel_font_height),
-      SK_ColorBLACK,
-      gfx::Rect(ToPixels(url_x), 0, ToPixels(url_width), ToPixels(kHeight)),
-      text_flags);
+  if (!gurl_.is_empty()) {
+    if (last_drawn_gurl_ != gurl_) {
+      // Draw text based on pixel sizes rather than meters, for correct font
+      // sizing.
+      int pixel_font_height = texture_size.height() * kFontHeight / kHeight;
+      float url_x = kBackButtonWidth + kSeparatorWidth + kSecurityFieldWidth;
+      float url_width = kWidth - url_x - kUrlRightMargin;
+      gfx::Rect text_bounds(ToPixels(url_x), 0, ToPixels(url_width),
+                            ToPixels(kHeight));
+      gurl_render_texts_ =
+          PrepareDrawStringRect(base::UTF8ToUTF16(gurl_.spec()),
+                                GetDefaultFontList(pixel_font_height),
+                                SK_ColorBLACK, &text_bounds, TEXT_ALIGN_LEFT);
+      last_drawn_gurl_ = gurl_;
+    }
+    for (auto& render_text : gurl_render_texts_)
+      render_text->Draw(&gfx_canvas);
+  }
 }
 
 gfx::Size UrlBarTexture::GetPreferredTextureSize(int maximum_width) const {
   return gfx::Size(maximum_width, maximum_width * kHeight / kWidth);
 }
 
 gfx::SizeF UrlBarTexture::GetDrawnSize() const {
   return size_;
 }
 
 }  // namespace vr_shell