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// Copyright (c) 2012 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/pango_util.h"
#include <cairo/cairo.h>
#include <pango/pango.h>
#include <pango/pangocairo.h>
#include <string>
#include <algorithm>
#include <map>
#include "base/logging.h"
#include "base/strings/utf_string_conversions.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/font_list.h"
#include "ui/gfx/font_render_params.h"
#include "ui/gfx/linux_font_delegate.h"
#include "ui/gfx/platform_font_pango.h"
#include "ui/gfx/text_utils.h"
namespace gfx {
namespace {
// Marker for accelerators in the text.
const gunichar kAcceleratorChar = '&';
// Creates and returns a PangoContext. The caller owns the context.
PangoContext* GetPangoContext() {
PangoFontMap* font_map = pango_cairo_font_map_get_default();
return pango_font_map_create_context(font_map);
}
// Creates a new cairo_font_options_t based on |params|.
cairo_font_options_t* CreateCairoFontOptions(const FontRenderParams& params) {
cairo_font_options_t* cairo_font_options = cairo_font_options_create();
FontRenderParams::SubpixelRendering subpixel = params.subpixel_rendering;
if (!params.antialiasing) {
cairo_font_options_set_antialias(cairo_font_options, CAIRO_ANTIALIAS_NONE);
} else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_NONE) {
cairo_font_options_set_antialias(cairo_font_options, CAIRO_ANTIALIAS_GRAY);
} else {
cairo_font_options_set_antialias(cairo_font_options,
CAIRO_ANTIALIAS_SUBPIXEL);
cairo_subpixel_order_t cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_DEFAULT;
if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_RGB)
cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_RGB;
else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_BGR)
cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_BGR;
else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_VRGB)
cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_VRGB;
else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_VBGR)
cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_VBGR;
else
NOTREACHED() << "Unhandled subpixel rendering type " << subpixel;
cairo_font_options_set_subpixel_order(cairo_font_options,
cairo_subpixel_order);
}
if (params.hinting == FontRenderParams::HINTING_NONE ||
params.subpixel_positioning) {
cairo_font_options_set_hint_style(cairo_font_options,
CAIRO_HINT_STYLE_NONE);
cairo_font_options_set_hint_metrics(cairo_font_options,
CAIRO_HINT_METRICS_OFF);
} else {
cairo_hint_style_t cairo_hint_style = CAIRO_HINT_STYLE_DEFAULT;
if (params.hinting == FontRenderParams::HINTING_SLIGHT)
cairo_hint_style = CAIRO_HINT_STYLE_SLIGHT;
else if (params.hinting == FontRenderParams::HINTING_MEDIUM)
cairo_hint_style = CAIRO_HINT_STYLE_MEDIUM;
else if (params.hinting == FontRenderParams::HINTING_FULL)
cairo_hint_style = CAIRO_HINT_STYLE_FULL;
else
NOTREACHED() << "Unhandled hinting style " << params.hinting;
cairo_font_options_set_hint_style(cairo_font_options, cairo_hint_style);
cairo_font_options_set_hint_metrics(cairo_font_options,
CAIRO_HINT_METRICS_ON);
}
return cairo_font_options;
}
// Returns the DPI that should be used by Pango.
double GetPangoDPI() {
static double dpi = -1.0;
if (dpi < 0.0) {
const gfx::LinuxFontDelegate* delegate = gfx::LinuxFontDelegate::instance();
if (delegate)
dpi = delegate->GetFontDPI();
if (dpi <= 0.0)
dpi = 96.0;
}
return dpi;
}
// Returns the number of pixels in a point.
// - multiply a point size by this to get pixels ("device units")
// - divide a pixel size by this to get points
double GetPixelsInPoint() {
static double pixels_in_point = GetPangoDPI() / 72.0; // 72 points in an inch
return pixels_in_point;
}
} // namespace
void SetUpPangoLayout(
PangoLayout* layout,
const base::string16& text,
const FontList& font_list,
base::i18n::TextDirection text_direction,
int flags) {
cairo_font_options_t* cairo_font_options = CreateCairoFontOptions(
font_list.GetPrimaryFont().GetFontRenderParams());
// If we got an explicit request to turn off subpixel rendering, disable it.
if ((flags & Canvas::NO_SUBPIXEL_RENDERING) &&
(cairo_font_options_get_antialias(cairo_font_options) ==
CAIRO_ANTIALIAS_SUBPIXEL))
cairo_font_options_set_antialias(cairo_font_options, CAIRO_ANTIALIAS_GRAY);
// 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);
cairo_font_options_destroy(cairo_font_options);
cairo_font_options = NULL;
// Set Pango's base text direction explicitly from |text_direction|.
pango_layout_set_auto_dir(layout, FALSE);
pango_context_set_base_dir(pango_layout_get_context(layout),
(text_direction == base::i18n::RIGHT_TO_LEFT ?
PANGO_DIRECTION_RTL : PANGO_DIRECTION_LTR));
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.
// Ensure that the text is only on one line.
pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_NONE);
pango_layout_set_width(layout, -1);
}
// Set the layout's resolution to match the resolution used to convert from
// points to pixels.
pango_cairo_context_set_resolution(pango_layout_get_context(layout),
GetPangoDPI());
// Set text and accelerator character if needed.
if (flags & Canvas::SHOW_PREFIX) {
// Escape the text string to be used as markup.
std::string utf8 = base::UTF16ToUTF8(text);
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 {
std::string utf8;
// Remove the ampersand character. A double ampersand is output as
// a single ampersand.
if (flags & Canvas::HIDE_PREFIX) {
DCHECK_EQ(1, g_unichar_to_utf8(kAcceleratorChar, NULL));
base::string16 accelerator_removed =
RemoveAcceleratorChar(text,
static_cast<base::char16>(kAcceleratorChar),
NULL, NULL);
utf8 = base::UTF16ToUTF8(accelerator_removed);
} else {
utf8 = base::UTF16ToUTF8(text);
}
pango_layout_set_text(layout, utf8.data(), utf8.size());
}
ScopedPangoFontDescription desc(pango_font_description_from_string(
font_list.GetFontDescriptionString().c_str()));
pango_layout_set_font_description(layout, desc.get());
}
int GetPangoFontSizeInPixels(PangoFontDescription* pango_font) {
// If the size is absolute, then it's in Pango units rather than points. There
// are PANGO_SCALE Pango units in a device unit (pixel).
if (pango_font_description_get_size_is_absolute(pango_font))
return pango_font_description_get_size(pango_font) / PANGO_SCALE;
// Otherwise, we need to convert from points.
return static_cast<int>(GetPixelsInPoint() *
pango_font_description_get_size(pango_font) / PANGO_SCALE + 0.5);
}
PangoFontMetrics* GetPangoFontMetrics(PangoFontDescription* desc) {
static std::map<int, PangoFontMetrics*>* desc_to_metrics = NULL;
static PangoContext* context = NULL;
if (!context) {
context = GetPangoContext();
pango_context_set_language(context, pango_language_get_default());
}
if (!desc_to_metrics)
desc_to_metrics = new std::map<int, PangoFontMetrics*>();
const int desc_hash = pango_font_description_hash(desc);
std::map<int, PangoFontMetrics*>::iterator i =
desc_to_metrics->find(desc_hash);
if (i == desc_to_metrics->end()) {
PangoFontMetrics* metrics = pango_context_get_metrics(context, desc, NULL);
desc_to_metrics->insert(std::make_pair(desc_hash, metrics));
return metrics;
}
return i->second;
}
} // namespace gfx
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