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/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file system_fonts.h
* @brief Provides the system font configurations.
*
* These APIs provides the list of system installed font files with additional metadata about the
* font.
*
* The ASystemFontIterator_open method will give you an iterator which can iterate all system
* installed font files as shown in the following example.
*
* \code{.cpp}
* ASystemFontIterator* iterator = ASystemFontIterator_open();
* ASystemFont* font = NULL;
*
* while ((font = ASystemFontIterator_next(iterator)) != nullptr) {
* // Look if the font is your desired one.
* if (ASystemFont_getWeight(font) == 400 && !ASystemFont_isItalic(font)
* && ASystemFont_getLocale(font) == NULL) {
* break;
* }
* ASystemFont_close(font);
* }
* ASystemFontIterator_close(iterator);
*
* int fd = open(ASystemFont_getFontFilePath(font), O_RDONLY);
* int collectionIndex = ASystemFont_getCollectionINdex(font);
* std::vector<std::pair<uint32_t, float>> variationSettings;
* for (size_t i = 0; i < ASystemFont_getAxisCount(font); ++i) {
* variationSettings.push_back(std::make_pair(
* ASystemFont_getAxisTag(font, i),
* ASystemFont_getAxisValue(font, i)));
* }
* ASystemFont_close(font);
*
* // Use this font for your text rendering engine.
*
* \endcode
*
* Available since API level 29.
*/
#ifndef ANDROID_SYSTEM_FONTS_H
#define ANDROID_SYSTEM_FONTS_H
#include <stdbool.h>
#include <stddef.h>
#include <sys/cdefs.h>
/******************************************************************
*
* IMPORTANT NOTICE:
*
* This file is part of Android's set of stable system headers
* exposed by the Android NDK (Native Development Kit).
*
* Third-party source AND binary code relies on the definitions
* here to be FROZEN ON ALL UPCOMING PLATFORM RELEASES.
*
* - DO NOT MODIFY ENUMS (EXCEPT IF YOU ADD NEW 32-BIT VALUES)
* - DO NOT MODIFY CONSTANTS OR FUNCTIONAL MACROS
* - DO NOT CHANGE THE SIGNATURE OF FUNCTIONS IN ANY WAY
* - DO NOT CHANGE THE LAYOUT OR SIZE OF STRUCTURES
*/
__BEGIN_DECLS
#if __ANDROID_API__ >= 29
enum {
/** The minimum value fot the font weight value. */
ASYSTEM_FONT_WEIGHT_MIN = 0,
/** A font weight value for the thin weight. */
ASYSTEM_FONT_WEIGHT_THIN = 100,
/** A font weight value for the extra-light weight. */
ASYSTEM_FONT_WEIGHT_EXTRA_LIGHT = 200,
/** A font weight value for the light weight. */
ASYSTEM_FONT_WEIGHT_LIGHT = 300,
/** A font weight value for the normal weight. */
ASYSTEM_FONT_WEIGHT_NORMAL = 400,
/** A font weight value for the medium weight. */
ASYSTEM_FONT_WEIGHT_MEDIUM = 500,
/** A font weight value for the semi-bold weight. */
ASYSTEM_FONT_WEIGHT_SEMI_BOLD = 600,
/** A font weight value for the bold weight. */
ASYSTEM_FONT_WEIGHT_BOLD = 700,
/** A font weight value for the extra-bold weight. */
ASYSTEM_FONT_WEIGHT_EXTRA_BOLD = 800,
/** A font weight value for the black weight. */
ASYSTEM_FONT_WEIGHT_BLACK = 900,
/** The maximum value for the font weight value. */
ASYSTEM_FONT_WEIGHT_MAX = 1000
};
/**
* ASystemFontIterator provides access to the system font configuration.
*
* ASystemFontIterator is an iterator for all available system font settings.
* This iterator is not a thread-safe object. Do not pass this iterator to other threads.
*/
struct ASystemFontIterator;
/**
* ASystemFont provides information of the single system font configuration.
*/
struct ASystemFont;
/**
* Create a system font iterator.
*
* Use ASystemFont_close() to close the iterator.
*
* \return a pointer for a newly allocated iterator, nullptr on failure.
*/
ASystemFontIterator* _Nullable ASystemFontIterator_open() __INTRODUCED_IN(29);
/**
* Close an opened system font iterator, freeing any related resources.
*
* \param iterator a pointer of an iterator for the system fonts. Do nothing if NULL is passed.
*/
void ASystemFontIterator_close(ASystemFontIterator* _Nullable iterator) __INTRODUCED_IN(29);
/**
* Move to the next system font.
*
* \param iterator an iterator for the system fonts. Passing NULL is not allowed.
* \return a font. If no more font is available, returns nullptr. You need to release the returned
* font by ASystemFont_close when it is no longer needed.
*/
ASystemFont* _Nullable ASystemFontIterator_next(ASystemFontIterator* _Nonnull iterator) __INTRODUCED_IN(29);
/**
* Close an ASystemFont returned by ASystemFontIterator_next.
*
* \param font a font returned by ASystemFontIterator_next or ASystemFont_matchFamilyStyleCharacter.
* Do nothing if NULL is passed.
*/
void ASystemFont_close(ASystemFont* _Nullable font) __INTRODUCED_IN(29);
/**
* Select the best font from given parameters.
*
* Only generic font families are supported.
* For more information about generic font families, read [W3C spec](https://www.w3.org/TR/css-fonts-4/#generic-font-families)
*
* Even if no font can render the given text, this function will return a non-null result for
* drawing Tofu character.
*
* Examples:
* \code{.cpp}
* // Simple font query for the ASCII character.
* std::vector<uint16_t> text = { 'A' };
* ASystemFont font = ASystemFont_matchFamilyStyleCharacter(
* "sans", 400, false, "en-US", text.data(), text.length(), &runLength);
* // runLength will be 1 and the font will points a valid font file.
*
* // Querying font for CJK characters
* std::vector<uint16_t> text = { 0x9AA8 };
* ASystemFont font = ASystemFont_matchFamilyStyleCharacter(
* "sans", 400, false, "zh-CN,ja-JP", text.data(), text.length(), &runLength);
* // runLength will be 1 and the font will points a Simplified Chinese font.
* ASystemFont font = ASystemFont_matchFamilyStyleCharacter(
* "sans", 400, false, "ja-JP,zh-CN", text.data(), text.length(), &runLength);
* // runLength will be 1 and the font will points a Japanese font.
*
* // Querying font for text/color emoji
* std::vector<uint16_t> text = { 0xD83D, 0xDC68, 0x200D, 0x2764, 0xFE0F, 0x200D, 0xD83D, 0xDC68 };
* ASystemFont font = ASystemFont_matchFamilyStyleCharacter(
* "sans", 400, false, "en-US", text.data(), text.length(), &runLength);
* // runLength will be 8 and the font will points a color emoji font.
*
* // Mixture of multiple script of characters.
* // 0x05D0 is a Hebrew character and 0x0E01 is a Thai character.
* std::vector<uint16_t> text = { 0x05D0, 0x0E01 };
* ASystemFont font = ASystemFont_matchFamilyStyleCharacter(
* "sans", 400, false, "en-US", text.data(), text.length(), &runLength);
* // runLength will be 1 and the font will points a Hebrew font.
* \endcode
*
* \param familyName a null character terminated font family name
* \param weight a font weight value. Only from 0 to 1000 value is valid
* \param italic true if italic, otherwise false.
* \param languageTags a null character terminated comma separated IETF BCP47 compliant language
* tags.
* \param text a UTF-16 encoded text buffer to be rendered. Do not pass empty string.
* \param textLength a length of the given text buffer. This must not be zero.
* \param runLengthOut if not null, the font run length will be filled.
* \return a font to be used for given text and params. You need to release the returned font by
* ASystemFont_close when it is no longer needed.
*/
ASystemFont* _Nonnull ASystemFont_matchFamilyStyleCharacter(
const char* _Nonnull familyName,
uint16_t weight,
bool italic,
const char* _Nonnull languageTags,
const uint16_t* _Nonnull text,
uint32_t textLength,
uint32_t* _Nullable runLengthOut) __INTRODUCED_IN(29);
/**
* Return an absolute path to the current font file.
*
* Here is a list of font formats returned by this method:
* <ul>
* <li>OpenType</li>
* <li>OpenType Font Collection</li>
* <li>TrueType</li>
* <li>TrueType Collection</li>
* </ul>
* The file extension could be one of *.otf, *.ttf, *.otc or *.ttc.
*
* The font file returned is guaranteed to be opend with O_RDONLY.
* Note that the returned pointer is valid until ASystemFont_close() is called for the given font.
*
* \param font a font object. Passing NULL is not allowed.
* \return a string of the font file path.
*/
const char* _Nonnull ASystemFont_getFontFilePath(const ASystemFont* _Nonnull font) __INTRODUCED_IN(29);
/**
* Return a weight value associated with the current font.
*
* The weight values are positive and less than or equal to 1000.
* Here are pairs of the common names and their values.
* <p>
* <table>
* <tr>
* <th align="center">Value</th>
* <th align="center">Name</th>
* <th align="center">NDK Definition</th>
* </tr>
* <tr>
* <td align="center">100</td>
* <td align="center">Thin</td>
* <td align="center">{@link ASYSTEM_FONT_WEIGHT_THIN}</td>
* </tr>
* <tr>
* <td align="center">200</td>
* <td align="center">Extra Light (Ultra Light)</td>
* <td align="center">{@link ASYSTEM_FONT_WEIGHT_EXTRA_LIGHT}</td>
* </tr>
* <tr>
* <td align="center">300</td>
* <td align="center">Light</td>
* <td align="center">{@link ASYSTEM_FONT_WEIGHT_LIGHT}</td>
* </tr>
* <tr>
* <td align="center">400</td>
* <td align="center">Normal (Regular)</td>
* <td align="center">{@link ASYSTEM_FONT_WEIGHT_NORMAL}</td>
* </tr>
* <tr>
* <td align="center">500</td>
* <td align="center">Medium</td>
* <td align="center">{@link ASYSTEM_FONT_WEIGHT_MEDIUM}</td>
* </tr>
* <tr>
* <td align="center">600</td>
* <td align="center">Semi Bold (Demi Bold)</td>
* <td align="center">{@link ASYSTEM_FONT_WEIGHT_SEMI_BOLD}</td>
* </tr>
* <tr>
* <td align="center">700</td>
* <td align="center">Bold</td>
* <td align="center">{@link ASYSTEM_FONT_WEIGHT_BOLD}</td>
* </tr>
* <tr>
* <td align="center">800</td>
* <td align="center">Extra Bold (Ultra Bold)</td>
* <td align="center">{@link ASYSTEM_FONT_WEIGHT_EXTRA_BOLD}</td>
* </tr>
* <tr>
* <td align="center">900</td>
* <td align="center">Black (Heavy)</td>
* <td align="center">{@link ASYSTEM_FONT_WEIGHT_BLACK}</td>
* </tr>
* </table>
* </p>
* Note that the weight value may fall in between above values, e.g. 250 weight.
*
* For more information about font weight, read [OpenType usWeightClass](https://docs.microsoft.com/en-us/typography/opentype/spec/os2#usweightclass)
*
* \param font a font object. Passing NULL is not allowed.
* \return a positive integer less than or equal to {@link ASYSTEM_FONT_MAX_WEIGHT} is returned.
*/
uint16_t ASystemFont_getWeight(const ASystemFont* _Nonnull font) __INTRODUCED_IN(29);
/**
* Return true if the current font is italic, otherwise returns false.
*
* \param font a font object. Passing NULL is not allowed.
* \return true if italic, otherwise false.
*/
bool ASystemFont_isItalic(const ASystemFont* _Nonnull font) __INTRODUCED_IN(29);
/**
* Return a IETF BCP47 compliant language tag associated with the current font.
*
* For information about IETF BCP47, read [Locale.forLanguageTag(java.lang.String)](https://developer.android.com/reference/java/util/Locale.html#forLanguageTag(java.lang.String)")
*
* Note that the returned pointer is valid until ASystemFont_close() is called.
*
* \param font a font object. Passing NULL is not allowed.
* \return a IETF BCP47 compliant langauge tag or nullptr if not available.
*/
const char* _Nullable ASystemFont_getLocale(const ASystemFont* _Nonnull font) __INTRODUCED_IN(29);
/**
* Return a font collection index value associated with the current font.
*
* In case the target font file is a font collection (e.g. .ttc or .otc), this
* returns a non-negative value as an font offset in the collection. This
* always returns 0 if the target font file is a regular font.
*
* \param font a font object. Passing NULL is not allowed.
* \return a font collection index.
*/
size_t ASystemFont_getCollectionIndex(const ASystemFont* _Nonnull font) __INTRODUCED_IN(29);
/**
* Return a count of font variation settings associated with the current font
*
* The font variation settings are provided as multiple tag-values pairs.
*
* For example, bold italic font may have following font variation settings:
* 'wght' 700, 'slnt' -12
* In this case, ASystemFont_getAxisCount returns 2 and ASystemFont_getAxisTag
* and ASystemFont_getAxisValue will return following values.
* \code{.cpp}
* ASystemFont* font = ASystemFontIterator_next(ite);
*
* // Returns the number of axes
* ASystemFont_getAxisCount(font); // Returns 2
*
* // Returns the tag-value pair for the first axis.
* ASystemFont_getAxisTag(font, 0); // Returns 'wght'(0x77676874)
* ASystemFont_getAxisValue(font, 0); // Returns 700.0
*
* // Returns the tag-value pair for the second axis.
* ASystemFont_getAxisTag(font, 1); // Returns 'slnt'(0x736c6e74)
* ASystemFont_getAxisValue(font, 1); // Returns -12.0
* \endcode
*
* For more information about font variation settings, read [Font Variations Table](https://docs.microsoft.com/en-us/typography/opentype/spec/fvar)
*
* \param font a font object. Passing NULL is not allowed.
* \return a number of font variation settings.
*/
size_t ASystemFont_getAxisCount(const ASystemFont* _Nonnull font) __INTRODUCED_IN(29);
/**
* Return an OpenType axis tag associated with the current font.
*
* See ASystemFont_getAxisCount for more details.
*
* \param font a font object. Passing NULL is not allowed.
* \param axisIndex an index to the font variation settings. Passing value larger than or
* equal to {@link ASystemFont_getAxisCount} is not allowed.
* \return an OpenType axis tag value for the given font variation setting.
*/
uint32_t ASystemFont_getAxisTag(const ASystemFont* _Nonnull font, uint32_t axisIndex)
__INTRODUCED_IN(29);
/**
* Return an OpenType axis value associated with the current font.
*
* See ASystemFont_getAxisCount for more details.
*
* \param font a font object. Passing NULL is not allowed.
* \param axisIndex an index to the font variation settings. Passing value larger than or
* equal to {@link ASYstemFont_getAxisCount} is not allwed.
* \return a float value for the given font variation setting.
*/
float ASystemFont_getAxisValue(const ASystemFont* _Nonnull font, uint32_t axisIndex)
__INTRODUCED_IN(29);
#endif // __ANDROID_API__ >= 29
__END_DECLS
#endif // ANDROID_SYSTEM_FONTS_H