Move app/gfx/canvas and app/gfx/font to gfx/.

TBR=darin
BUG=none
TEST=none

Review URL: http://codereview.chromium.org/1132006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@42312 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 286 insertions, 0 deletions

diff --git a/gfx/canvas_win.cc b/gfx/canvas_win.cc
new file mode 100644
index 0000000..be9756a
--- /dev/null
+++ b/gfx/canvas_win.cc
@@ -0,0 +1,286 @@
+// Copyright (c) 2010 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 "gfx/canvas.h"
+
+#include <limits>
+
+#include "base/i18n/rtl.h"
+#include "gfx/font.h"
+#include "gfx/rect.h"
+#include "third_party/skia/include/core/SkShader.h"
+
+namespace {
+
+// We make sure that LTR text we draw in an RTL context is modified
+// appropriately to make sure it maintains it LTR orientation.
+void DoDrawText(HDC hdc, const std::wstring& text,
+                RECT* text_bounds, int flags) {
+  std::wstring localized_text;
+  const wchar_t* string_ptr = text.c_str();
+  int string_size = static_cast<int>(text.length());
+  // Only adjust string directionality if both of the following are true:
+  // 1. The current locale is RTL.
+  // 2. The string itself has RTL directionality.
+  if (flags & DT_RTLREADING) {
+    if (base::i18n::AdjustStringForLocaleDirection(text, &localized_text)) {
+      string_ptr = localized_text.c_str();
+      string_size = static_cast<int>(localized_text.length());
+    }
+  }
+
+  DrawText(hdc, string_ptr, string_size, text_bounds, flags);
+}
+
+// Compute the windows flags necessary to implement the provided text Canvas
+// flags.
+int ComputeFormatFlags(int flags, const std::wstring& text) {
+  // Setting the text alignment explicitly in case it hasn't already been set.
+  // This will make sure that we don't align text to the left on RTL locales
+  // just because no alignment flag was passed to DrawStringInt().
+  if (!(flags & (gfx::Canvas::TEXT_ALIGN_CENTER |
+                 gfx::Canvas::TEXT_ALIGN_RIGHT |
+                 gfx::Canvas::TEXT_ALIGN_LEFT))) {
+    flags |= gfx::Canvas::DefaultCanvasTextAlignment();
+  }
+
+  // horizontal alignment
+  int f = 0;
+  if (flags & gfx::Canvas::TEXT_ALIGN_CENTER)
+    f |= DT_CENTER;
+  else if (flags & gfx::Canvas::TEXT_ALIGN_RIGHT)
+    f |= DT_RIGHT;
+  else
+    f |= DT_LEFT;
+
+  // vertical alignment
+  if (flags & gfx::Canvas::TEXT_VALIGN_TOP)
+    f |= DT_TOP;
+  else if (flags & gfx::Canvas::TEXT_VALIGN_BOTTOM)
+    f |= DT_BOTTOM;
+  else
+    f |= DT_VCENTER;
+
+  if (flags & gfx::Canvas::MULTI_LINE) {
+    f |= DT_WORDBREAK;
+    if (flags & gfx::Canvas::CHARACTER_BREAK)
+      f |= DT_EDITCONTROL;  // Turns on character breaking (not documented)
+    else if (!(flags & gfx::Canvas::NO_ELLIPSIS))
+      f |= DT_WORD_ELLIPSIS;
+  } else {
+    f |= DT_SINGLELINE;
+  }
+
+  if (flags & gfx::Canvas::HIDE_PREFIX)
+    f |= DT_HIDEPREFIX;
+  else if ((flags & gfx::Canvas::SHOW_PREFIX) == 0)
+    f |= DT_NOPREFIX;
+
+  if (!(flags & gfx::Canvas::NO_ELLIPSIS))
+    f |= DT_END_ELLIPSIS;
+
+  // In order to make sure RTL/BiDi strings are rendered correctly, we must
+  // pass the flag DT_RTLREADING to DrawText (when the locale's language is
+  // a right-to-left language) so that Windows does the right thing.
+  //
+  // In addition to correctly displaying text containing both RTL and LTR
+  // elements (for example, a string containing a telephone number within a
+  // sentence in Hebrew, or a sentence in Hebrew that contains a word in
+  // English) this flag also makes sure that if there is not enough space to
+  // display the entire string, the ellipsis is displayed on the left hand side
+  // of the truncated string and not on the right hand side.
+  //
+  // We make a distinction between Chrome UI strings and text coming from a web
+  // page.
+  //
+  // For text coming from a web page we determine the alignment based on the
+  // first character with strong directionality. If the directionality of the
+  // first character with strong directionality in the text is LTR, the
+  // alignment is set to DT_LEFT, and the directionality should not be set as
+  // DT_RTLREADING.
+  //
+  // This heuristic doesn't work for Chrome UI strings since even in RTL
+  // locales, some of those might start with English text but we know they're
+  // localized so we always want them to be right aligned, and their
+  // directionality should be set as DT_RTLREADING.
+  //
+  // Caveat: If the string is purely LTR, don't set DTL_RTLREADING since when
+  // the flag is set, LRE-PDF don't have the desired effect of rendering
+  // multiline English-only text as LTR.
+  //
+  // Note that if the caller is explicitly requesting displaying the text
+  // using RTL directionality then we respect that and pass DT_RTLREADING to
+  // ::DrawText even if the locale is LTR.
+  if ((flags & gfx::Canvas::FORCE_RTL_DIRECTIONALITY) ||
+      (base::i18n::IsRTL() &&
+       (f & DT_RIGHT) && base::i18n::StringContainsStrongRTLChars(text))) {
+    f |= DT_RTLREADING;
+  }
+
+  return f;
+}
+
+}  // anonymous namespace
+
+namespace gfx {
+
+Canvas::Canvas(int width, int height, bool is_opaque)
+    : skia::PlatformCanvas(width, height, is_opaque) {
+}
+
+Canvas::Canvas() : skia::PlatformCanvas() {
+}
+
+Canvas::~Canvas() {
+}
+
+// static
+void Canvas::SizeStringInt(const std::wstring& text,
+                           const gfx::Font& font,
+                           int *width, int *height, int flags) {
+  // Clamp the max amount of text we'll measure to 2K.  When the string is
+  // actually drawn, it will be clipped to whatever size box is provided, and
+  // the time to do that doesn't depend on the length being clipped off.
+  const int kMaxStringLength = 2048;
+  std::wstring clamped_string(text.substr(0, kMaxStringLength));
+
+  if (*width == 0) {
+    // If multi-line + character break are on, the computed width will be one
+    // character wide (useless).  Furthermore, if in this case the provided text
+    // contains very long "words" (substrings without a word-breaking point),
+    // DrawText() can run extremely slowly (e.g. several seconds).  So in this
+    // case, we turn character breaking off to get a more accurate "desired"
+    // width and avoid the slowdown.
+    if (flags & (gfx::Canvas::MULTI_LINE | gfx::Canvas::CHARACTER_BREAK))
+      flags &= ~gfx::Canvas::CHARACTER_BREAK;
+
+    // Weird undocumented behavior: if the width is 0, DoDrawText() won't
+    // calculate a size at all.  So set it to 1, which it will then change.
+    if (!text.empty())
+      *width = 1;
+  }
+  RECT r = { 0, 0, *width, *height };
+
+  HDC dc = GetDC(NULL);
+  HFONT old_font = static_cast<HFONT>(SelectObject(dc, font.hfont()));
+  DoDrawText(dc, clamped_string, &r,
+             ComputeFormatFlags(flags, clamped_string) | DT_CALCRECT);
+  SelectObject(dc, old_font);
+  ReleaseDC(NULL, dc);
+
+  *width = r.right;
+  *height = r.bottom;
+}
+
+void Canvas::DrawStringInt(const std::wstring& text, HFONT font,
+                           const SkColor& color, int x, int y, int w, int h,
+                           int flags) {
+  if (!IntersectsClipRectInt(x, y, w, h))
+    return;
+
+  RECT text_bounds = { x, y, x + w, y + h };
+  HDC dc = beginPlatformPaint();
+  SetBkMode(dc, TRANSPARENT);
+  HFONT old_font = (HFONT)SelectObject(dc, font);
+  COLORREF brush_color = RGB(SkColorGetR(color), SkColorGetG(color),
+                             SkColorGetB(color));
+  SetTextColor(dc, brush_color);
+
+  int f = ComputeFormatFlags(flags, text);
+  DoDrawText(dc, text, &text_bounds, f);
+  endPlatformPaint();
+
+  // Restore the old font. This way we don't have to worry if the caller
+  // deletes the font and the DC lives longer.
+  SelectObject(dc, old_font);
+
+  // Windows will have cleared the alpha channel of the text we drew. Assume
+  // we're drawing to an opaque surface, or at least the text rect area is
+  // opaque.
+  getTopPlatformDevice().makeOpaque(x, y, w, h);
+}
+
+void Canvas::DrawStringInt(const std::wstring& text,
+                           const gfx::Font& font,
+                           const SkColor& color,
+                           int x, int y, int w, int h, int flags) {
+  DrawStringInt(text, font.hfont(), color, x, y, w, h, flags);
+}
+
+// Checks each pixel immediately adjacent to the given pixel in the bitmap. If
+// any of them are not the halo color, returns true. This defines the halo of
+// pixels that will appear around the text. Note that we have to check each
+// pixel against both the halo color and transparent since DrawStringWithHalo
+// will modify the bitmap as it goes, and clears pixels shouldn't count as
+// changed.
+static bool pixelShouldGetHalo(const SkBitmap& bitmap, int x, int y,
+                               SkColor halo_color) {
+  if (x > 0 &&
+      *bitmap.getAddr32(x - 1, y) != halo_color &&
+      *bitmap.getAddr32(x - 1, y) != 0)
+    return true;  // Touched pixel to the left.
+  if (x < bitmap.width() - 1 &&
+      *bitmap.getAddr32(x + 1, y) != halo_color &&
+      *bitmap.getAddr32(x + 1, y) != 0)
+    return true;  // Touched pixel to the right.
+  if (y > 0 &&
+      *bitmap.getAddr32(x, y - 1) != halo_color &&
+      *bitmap.getAddr32(x, y - 1) != 0)
+    return true;  // Touched pixel above.
+  if (y < bitmap.height() - 1 &&
+      *bitmap.getAddr32(x, y + 1) != halo_color &&
+      *bitmap.getAddr32(x, y + 1) != 0)
+    return true;  // Touched pixel below.
+  return false;
+}
+
+void Canvas::DrawStringWithHalo(const std::wstring& text,
+                                const gfx::Font& font,
+                                const SkColor& text_color,
+                                const SkColor& halo_color_in,
+                                int x, int y, int w, int h,
+                                int flags) {
+  // Some callers will have semitransparent halo colors, which we don't handle
+  // (since the resulting image can have 1-bit transparency only).
+  SkColor halo_color = halo_color_in | 0xFF000000;
+
+  // Create a temporary buffer filled with the halo color. It must leave room
+  // for the 1-pixel border around the text.
+  Canvas text_canvas(w + 2, h + 2, true);
+  SkPaint bkgnd_paint;
+  bkgnd_paint.setColor(halo_color);
+  text_canvas.FillRectInt(0, 0, w + 2, h + 2, bkgnd_paint);
+
+  // Draw the text into the temporary buffer. This will have correct
+  // ClearType since the background color is the same as the halo color.
+  text_canvas.DrawStringInt(text, font, text_color, 1, 1, w, h, flags);
+
+  // Windows will have cleared the alpha channel for the pixels it drew. Make it
+  // opaque. We have to do this first since pixelShouldGetHalo will check for
+  // 0 to see if a pixel has been modified to transparent, and black text that
+  // Windows draw will look transparent to it!
+  text_canvas.getTopPlatformDevice().makeOpaque(0, 0, w + 2, h + 2);
+
+  uint32_t halo_premul = SkPreMultiplyColor(halo_color);
+  SkBitmap& text_bitmap = const_cast<SkBitmap&>(
+      text_canvas.getTopPlatformDevice().accessBitmap(true));
+  for (int cur_y = 0; cur_y < h + 2; cur_y++) {
+    uint32_t* text_row = text_bitmap.getAddr32(0, cur_y);
+    for (int cur_x = 0; cur_x < w + 2; cur_x++) {
+      if (text_row[cur_x] == halo_premul) {
+        // This pixel was not touched by the text routines. See if it borders
+        // a touched pixel in any of the 4 directions (not diagonally).
+        if (!pixelShouldGetHalo(text_bitmap, cur_x, cur_y, halo_premul))
+          text_row[cur_x] = 0;  // Make transparent.
+      } else {
+        text_row[cur_x] |= 0xff << SK_A32_SHIFT;  // Make opaque.
+      }
+    }
+  }
+
+  // Draw the halo bitmap with blur.
+  drawBitmap(text_bitmap, SkIntToScalar(x - 1), SkIntToScalar(y - 1));
+}
+
+}  // namespace gfx