VR: Avoiding regeneration of RenderText objects for texture rendering

chrome/browser/android/vr_shell/textures/insecure_content_permanent_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/insecure_content_permanent_texture.h"
 
 #include "cc/paint/skia_paint_canvas.h"
 #include "components/strings/grit/components_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/font_list.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/vector2d.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 {
 
 const SkColor kBackgroundColor = SK_ColorWHITE;
 const SkColor kForegroundColor = 0xFF444444;
 constexpr float kBorderFactor = 0.1;
 constexpr float kIconSizeFactor = 0.7;
 constexpr float kFontSizeFactor = 0.40;
 constexpr float kTextHeightFactor = 1.0 - 2 * kBorderFactor;
 constexpr float kTextWidthFactor = 4.0 - 3 * kBorderFactor - kIconSizeFactor;
 
 }  // namespace
 
 InsecureContentPermanentTexture::InsecureContentPermanentTexture() = default;
 
 InsecureContentPermanentTexture::~InsecureContentPermanentTexture() = default;
 
 void InsecureContentPermanentTexture::Draw(SkCanvas* sk_canvas,
                                            const gfx::Size& texture_size) {
   cc::SkiaPaintCanvas paint_canvas(sk_canvas);
   gfx::Canvas gfx_canvas(&paint_canvas, 1.0f);
   gfx::Canvas* canvas = &gfx_canvas;
 
   DCHECK(texture_size.height() * 4 == texture_size.width());
   size_.set_height(texture_size.height());
-  int max_width = texture_size.width();
-  cc::PaintFlags flags;
-  flags.setColor(kBackgroundColor);
-
-  int text_flags = gfx::Canvas::TEXT_ALIGN_CENTER | gfx::Canvas::NO_ELLIPSIS;
+  SkPaint paint;
+  paint.setColor(kBackgroundColor);
   auto text =
       l10n_util::GetStringUTF16(IDS_PAGE_INFO_INSECURE_WEBVR_CONTENT_PERMANENT);
   auto fonts = GetFontList(size_.height() * kFontSizeFactor, text);
-  int text_height = kTextHeightFactor * size_.height();
-  int text_width = kTextWidthFactor * size_.height();
-  gfx::Canvas::SizeStringInt(text, fonts, &text_width, &text_height, 0,
-                             text_flags);
-  // Giving some extra width without reaching the texture limit.
-  text_width =
-      static_cast<int>(std::min(text_width + 2 * kBorderFactor * size_.height(),
-                                kTextWidthFactor * size_.height()));
-  size_.set_width((3 * kBorderFactor + kIconSizeFactor) * size_.height() +
-                  text_width);
-  DCHECK_LE(size_.width(), max_width);
-  canvas->DrawRoundRect(gfx::Rect(size_.width(), size_.height()),
-                        size_.height() * kBorderFactor, flags);
+  gfx::Rect text_size(0, kTextHeightFactor * size_.height());
+
+  std::vector<std::unique_ptr<gfx::RenderText>> lines =
+      PrepareDrawStringRect(text, fonts, kForegroundColor, &text_size, 0);
+
+  DCHECK_LE(text_size.width(), kTextWidthFactor * size_.height());
+  // Setting background size giving some extra lateral padding to the text.
+  size_.set_width((5 * kBorderFactor + kIconSizeFactor) * size_.height() +
+                  text_size.width());
+  float radius = size_.height() * kBorderFactor;
+  sk_canvas->drawRoundRect(SkRect::MakeWH(size_.width(), size_.height()),

[mthiesse, 2017/05/12 01:14:38]

Why the change from canvas->DrawRoundRect?

[acondor_, 2017/05/12 14:54:23]

To be compliant with how we are doing the URL bar. The idea is to only use
gfx::Canvas when there's no other option, to avoid it's overhead.

+                           radius, radius, paint);
 
   canvas->Save();
-  canvas->Translate(
-      gfx::Vector2d(IsRTL() ? 2 * kBorderFactor * size_.height() + text_width
-                            : size_.height() * kBorderFactor,
-                    size_.height() * (1.0 - kIconSizeFactor) / 2.0));
+  canvas->Translate(gfx::Vector2d(
+      IsRTL() ? 3 * kBorderFactor * size_.height() + text_size.width()
+              : size_.height() * kBorderFactor,

[mthiesse, 2017/05/12 01:14:38]

Shouldn't this be "2 * size_.height() * kBorderFactor" now?

[acondor_, 2017/05/12 14:54:23]

Actually the RTL should be 4, and the LRT only 1.

+      size_.height() * (1.0 - kIconSizeFactor) / 2.0));
   PaintVectorIcon(canvas, ui::kInfoOutlineIcon,
                   size_.height() * kIconSizeFactor, kForegroundColor);
   canvas->Restore();
 
   canvas->Save();
   canvas->Translate(gfx::Vector2d(
       size_.height() *
           (IsRTL() ? kBorderFactor : 2 * kBorderFactor + kIconSizeFactor),

[mthiesse, 2017/05/12 01:14:38]

Shouldn't this be "4 * kBorderFactor + kIconSizeFactor" now?

[acondor_, 2017/05/12 14:54:23]

2 for RTL and 3 for LTR.

       size_.height() * kBorderFactor));
-  canvas->DrawStringRectWithFlags(
-      text, fonts, kForegroundColor,
-      gfx::Rect(text_width, kTextHeightFactor * size_.height()), text_flags);
+  for (auto& render_text : lines)
+    render_text->Draw(canvas);
   canvas->Restore();
 }
 
 gfx::Size InsecureContentPermanentTexture::GetPreferredTextureSize(
     int maximum_width) const {
   // Ensuring height is a quarter of the width.
   int height = maximum_width / 4;
   return gfx::Size(height * 4, height);
 }
 
 gfx::SizeF InsecureContentPermanentTexture::GetDrawnSize() const {
   return size_;
 }
 
 }  // namespace vr_shell