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// Copyright (c) 2006-2008 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/common/gfx/chrome_canvas.h"
#include <limits>
#include "base/gfx/rect.h"
#include "base/logging.h"
#include "skia/include/SkShader.h"
#include "chrome/common/gfx/chrome_font.h"
#include "chrome/common/l10n_util.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 (l10n_util::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
// ChromeCanvas flags.
int ComputeFormatFlags(int flags, const std::wstring& text) {
int f = 0;
// 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 & (ChromeCanvas::TEXT_ALIGN_CENTER |
ChromeCanvas::TEXT_ALIGN_RIGHT |
ChromeCanvas::TEXT_ALIGN_LEFT))) {
flags |= l10n_util::DefaultCanvasTextAlignment();
}
if (flags & ChromeCanvas::HIDE_PREFIX)
f |= DT_HIDEPREFIX;
else if ((flags & ChromeCanvas::SHOW_PREFIX) == 0)
f |= DT_NOPREFIX;
if (flags & ChromeCanvas::MULTI_LINE) {
f |= DT_WORDBREAK;
} else {
f |= DT_SINGLELINE | DT_VCENTER;
if (!(flags & ChromeCanvas::NO_ELLIPSIS))
f |= DT_END_ELLIPSIS;
}
// vertical alignment
if (flags & ChromeCanvas::TEXT_VALIGN_TOP)
f |= DT_TOP;
else if (flags & ChromeCanvas::TEXT_VALIGN_BOTTOM)
f |= DT_BOTTOM;
else
f |= DT_VCENTER;
// horizontal alignment
if (flags & ChromeCanvas::TEXT_ALIGN_CENTER)
f |= DT_CENTER;
else if (flags & ChromeCanvas::TEXT_ALIGN_RIGHT)
f |= DT_RIGHT;
else
f |= DT_LEFT;
// 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.
if (l10n_util::GetTextDirection() == l10n_util::RIGHT_TO_LEFT &&
(f & DT_RIGHT)) {
if (l10n_util::StringContainsStrongRTLChars(text)) {
f |= DT_RTLREADING;
}
}
return f;
}
} // anonymous namespace
ChromeCanvas::ChromeCanvas(int width, int height, bool is_opaque)
: skia::PlatformCanvasWin(width, height, is_opaque) {
}
ChromeCanvas::ChromeCanvas() : skia::PlatformCanvasWin() {
}
ChromeCanvas::~ChromeCanvas() {
}
// static
void ChromeCanvas::SizeStringInt(const std::wstring& text,
const ChromeFont& font,
int *width, int *height, int flags) {
HDC dc = GetDC(NULL);
HFONT old_font = static_cast<HFONT>(SelectObject(dc, font.hfont()));
RECT b;
b.left = 0;
b.top = 0;
b.right = *width;
if (b.right == 0 && !text.empty()) {
// Width needs to be at least 1 or else DoDrawText will not resize it.
b.right = 1;
}
b.bottom = *height;
DoDrawText(dc, text, &b, ComputeFormatFlags(flags, text) | DT_CALCRECT);
// 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);
*width = b.right;
*height = b.bottom;
ReleaseDC(NULL, dc);
}
void ChromeCanvas::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;
getTopPlatformDevice().prepareForGDI(x, y, w, h);
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);
getTopPlatformDevice().postProcessGDI(x, y, w, h);
}
void ChromeCanvas::DrawStringInt(const std::wstring& text,
const ChromeFont& font,
const SkColor& color,
int x, int y,
int w, int h) {
DrawStringInt(text, font, color, x, y, w, h,
l10n_util::DefaultCanvasTextAlignment());
}
void ChromeCanvas::DrawStringInt(const std::wstring& text,
const ChromeFont& font,
const SkColor& color,
int x, int y, int w, int h, int flags) {
DrawStringInt(text, font.hfont(), color, x, y, w, h, flags);
}
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