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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_GFX_FONT_LIST_H_
#define UI_GFX_FONT_LIST_H_
#include <string>
#include <vector>
#include "base/component_export.h"
#include "base/memory/scoped_refptr.h"
#include "ui/gfx/font.h"
namespace gfx {
class FontListImpl;
// FontList represents a list of fonts and provides metrics which are common
// across the fonts. FontList is copyable and quite cheap to copy.
//
// The format of font description strings is a subset of that used by Pango, as
// described at
// http://developer.gnome.org/pango/stable/pango-Fonts.html#pango-font-description-from-string
//
// Pango font description strings should not be passed directly into FontLists.
//
// The format is "<FONT_FAMILY_LIST>,[STYLES] <SIZE>", where:
// - FONT_FAMILY_LIST is a comma-separated list of font family names,
// - STYLES is an optional space-separated list of style names (case-sensitive
// "Italic" "Ultra-Light" "Light" "Normal" "Semi-Bold" "Bold" "Ultra-Bold"
// "Heavy" are supported), and
// - SIZE is an integer font size in pixels with the suffix "px"
//
// Here are examples of valid font description strings:
// - "Arial, Helvetica, Italic Semi-Bold 14px"
// - "Arial, 14px"
class COMPONENT_EXPORT(GFX) FontList {
public:
// Parses a FontList description string into |families_out|, |style_out| (a
// bitfield of gfx::Font::Style values), |size_pixels_out| and |weight_out|.
// Returns true if the string is properly-formed.
static bool ParseDescription(const std::string& description,
std::vector<std::string>* families_out,
int* style_out,
int* size_pixels_out,
Font::Weight* weight_out);
// Creates a font list with default font names, size and style, which are
// specified by SetDefaultFontDescription().
FontList();
// Creates a font list that is a clone of another font list.
FontList(const FontList& other);
// Creates a font list from a string representing font names, styles, and
// size.
explicit FontList(const std::string& font_description_string);
// Creates a font list from font names, styles, size and weight.
FontList(const std::vector<std::string>& font_names,
int font_style,
int font_size,
Font::Weight font_weight);
// Creates a font list from a Font vector.
// All fonts in this vector should have the same style and size.
explicit FontList(const std::vector<Font>& fonts);
// Creates a font list from a Font.
explicit FontList(const Font& font);
~FontList();
// Copies the given font list into this object.
FontList& operator=(const FontList& other);
// Sets the description string for default FontList construction. If it's
// empty, FontList will initialize using the default Font constructor.
//
// The client code must call this function before any call of the default
// constructor. This should be done on the UI thread.
//
// ui::ResourceBundle may call this function more than once when UI language
// is changed.
//
// Unit Tests should use ScopedDefaultFontDescription instead of calling this
// directly, to avoid leaving the default font description in an unexpected
// state for tests that run in the same process.
static void SetDefaultFontDescription(const std::string& font_description);
// Returns a new FontList with the same font names but resized and the given
// style and weight. |size_delta| is the size in pixels to add to the current
// font size. |font_style| specifies the new style, which is a bitmask of the
// values: Font::ITALIC and Font::UNDERLINE. |weight| is the requested font
// weight.
FontList Derive(int size_delta,
int font_style,
Font::Weight weight) const;
// Returns a new FontList with the same font names and style but resized.
// |size_delta| is the size in pixels to add to the current font size.
FontList DeriveWithSizeDelta(int size_delta) const;
// Returns a new FontList with the same font names, weight and size but the
// given style. |font_style| specifies the new style, which is a bitmask of
// the values: Font::ITALIC and Font::UNDERLINE.
FontList DeriveWithStyle(int font_style) const;
// Returns a new FontList with the same font name, size and style but with
// the given weight.
FontList DeriveWithWeight(Font::Weight weight) const;
// Shrinks the font size until the font list fits within |height| while
// having its cap height vertically centered. Returns a new FontList with
// the correct height.
//
// The expected layout:
// +--------+-----------------------------------------------+------------+
// | | y offset | space |
// | +--------+-------------------+------------------+ above |
// | | | | internal leading | cap height |
// | box | font | ascent (baseline) +------------------+------------+
// | height | height | | cap height |
// | | |-------------------+------------------+------------+
// | | | descent (height - baseline) | space |
// | +--------+--------------------------------------+ below |
// | | space at bottom | cap height |
// +--------+-----------------------------------------------+------------+
// Goal:
// center of box height == center of cap height
// (i.e. space above cap height == space below cap height)
// Restrictions:
// y offset >= 0
// space at bottom >= 0
// (i.e. Entire font must be visible inside the box.)
FontList DeriveWithHeightUpperBound(int height) const;
// Returns the height of this font list, which is max(ascent) + max(descent)
// for all the fonts in the font list.
int GetHeight() const;
// Returns the baseline of this font list, which is max(baseline) for all the
// fonts in the font list.
int GetBaseline() const;
// Returns the cap height of this font list.
// Currently returns the cap height of the primary font.
int GetCapHeight() const;
// Returns the expected number of horizontal pixels needed to display the
// specified length of characters. Call GetStringWidth() to retrieve the
// actual number.
int GetExpectedTextWidth(int length) const;
// Returns the |Font::FontStyle| style flags for this font list.
int GetFontStyle() const;
// Returns the font size in pixels.
int GetFontSize() const;
// Returns the font weight.
Font::Weight GetFontWeight() const;
// Returns the Font vector.
const std::vector<Font>& GetFonts() const;
// Returns the first font in the list.
const Font& GetPrimaryFont() const;
// Returns the first available font name. If there is no available font,
// returns the first font name. Empty entries are ignored.
// Used by Blink and webui to pick the primary standard/serif/sans/fixed/etc.
// fonts from region-specific IDS lists.
static std::string FirstAvailableOrFirst(const std::string& font_name_list);
private:
explicit FontList(FontListImpl* impl);
static const scoped_refptr<FontListImpl>& GetDefaultImpl();
scoped_refptr<FontListImpl> impl_;
};
} // namespace gfx
#endif // UI_GFX_FONT_LIST_H_
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