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// Copyright 2017 The Cobalt Authors. All Rights Reserved.
//
// 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.
// Module Overview: Starboard Accessibility module
//
// Provides access to the system options and settings related to accessibility.
#ifndef STARBOARD_ACCESSIBILITY_H_
#define STARBOARD_ACCESSIBILITY_H_
#include "starboard/export.h"
#include "starboard/types.h"
#ifdef __cplusplus
extern "C" {
#endif
// A group of settings related to text-to-speech functionality, for platforms
// that expose system settings for text-to-speech.
typedef struct SbAccessibilityTextToSpeechSettings {
// Whether this platform has a system setting for text-to-speech or not.
bool has_text_to_speech_setting;
// Whether the text-to-speech setting is enabled or not. This setting is only
// valid if |has_text_to_speech_setting| is set to true.
bool is_text_to_speech_enabled;
} SbAccessibilityTextToSpeechSettings;
// Get the platform settings related to the text-to-speech accessibility
// feature. This function returns false if |out_settings| is NULL or if it is
// not zero-initialized.
//
// |out_settings|: A pointer to a zero-initialized
// SbAccessibilityTextToSpeechSettings struct.
SB_EXPORT bool SbAccessibilityGetTextToSpeechSettings(
SbAccessibilityTextToSpeechSettings* out_settings);
typedef struct SbAccessibilityDisplaySettings {
// Whether this platform has a system setting for high contrast text or not.
bool has_high_contrast_text_setting;
// Whether the high contrast text setting is enabled or not.
bool is_high_contrast_text_enabled;
} SbAccessibilityDisplaySettings;
// Get the platform settings related to high contrast text.
// This function returns false if |out_settings| is NULL or if it is
// not zero-initialized.
//
// |out_settings|: A pointer to a zero-initialized
// SbAccessibilityDisplaySettings* struct.
SB_EXPORT bool SbAccessibilityGetDisplaySettings(
SbAccessibilityDisplaySettings* out_settings);
#if SB_HAS(CAPTIONS)
// Enum for possible closed captioning character edge styles.
typedef enum SbAccessibilityCaptionCharacterEdgeStyle {
kSbAccessibilityCaptionCharacterEdgeStyleNone,
kSbAccessibilityCaptionCharacterEdgeStyleRaised,
kSbAccessibilityCaptionCharacterEdgeStyleDepressed,
kSbAccessibilityCaptionCharacterEdgeStyleUniform,
kSbAccessibilityCaptionCharacterEdgeStyleDropShadow,
} SbAccessibilityCaptionCharacterEdgeStyle;
// Enum for possible closed captioning colors.
typedef enum SbAccessibilityCaptionColor {
kSbAccessibilityCaptionColorBlue,
kSbAccessibilityCaptionColorBlack,
kSbAccessibilityCaptionColorCyan,
kSbAccessibilityCaptionColorGreen,
kSbAccessibilityCaptionColorMagenta,
kSbAccessibilityCaptionColorRed,
kSbAccessibilityCaptionColorWhite,
kSbAccessibilityCaptionColorYellow,
} SbAccessibilityCaptionColor;
// Enum for possible closed captioning font families
typedef enum SbAccessibilityCaptionFontFamily {
kSbAccessibilityCaptionFontFamilyCasual,
kSbAccessibilityCaptionFontFamilyCursive,
kSbAccessibilityCaptionFontFamilyMonospaceSansSerif,
kSbAccessibilityCaptionFontFamilyMonospaceSerif,
kSbAccessibilityCaptionFontFamilyProportionalSansSerif,
kSbAccessibilityCaptionFontFamilyProportionalSerif,
kSbAccessibilityCaptionFontFamilySmallCapitals,
} SbAccessibilityCaptionFontFamily;
// Enum for possible closed captioning font size percentages.
typedef enum SbAccessibilityCaptionFontSizePercentage {
kSbAccessibilityCaptionFontSizePercentage25,
kSbAccessibilityCaptionFontSizePercentage50,
kSbAccessibilityCaptionFontSizePercentage75,
kSbAccessibilityCaptionFontSizePercentage100,
kSbAccessibilityCaptionFontSizePercentage125,
kSbAccessibilityCaptionFontSizePercentage150,
kSbAccessibilityCaptionFontSizePercentage175,
kSbAccessibilityCaptionFontSizePercentage200,
kSbAccessibilityCaptionFontSizePercentage225,
kSbAccessibilityCaptionFontSizePercentage250,
kSbAccessibilityCaptionFontSizePercentage275,
kSbAccessibilityCaptionFontSizePercentage300,
} SbAccessibilityCaptionFontSizePercentage;
// Enum for possible closed captioning opacity percentages.
typedef enum SbAccessibilityCaptionOpacityPercentage {
kSbAccessibilityCaptionOpacityPercentage0,
kSbAccessibilityCaptionOpacityPercentage25,
kSbAccessibilityCaptionOpacityPercentage50,
kSbAccessibilityCaptionOpacityPercentage75,
kSbAccessibilityCaptionOpacityPercentage100,
} SbAccessibilityCaptionOpacityPercentage;
// Enum for possible states of closed captioning properties.
typedef enum SbAccessibilityCaptionState {
// The property is not supported by the system. The application should provide
// a way to set this property, otherwise it will not be changeable.
// For any given closed captioning property, if its corresponding state
// property has a value of |kSbAccessibilityCaptionStateUnsupported|, then its
// own value is undefined. For example, if
// |SbAccessibilityCaptionColor::background_color_state| has a value of
// |kSbAccessibilityCaptionStateUnsupported|, then the value of
// |SbAccessibilityCaptionColor::background_color| is undefined.
kSbAccessibilityCaptionStateUnsupported = 0,
// The property is supported by the system, but the user has not set it.
// The application should provide a default setting for the property to
// handle this case.
kSbAccessibilityCaptionStateUnset,
// The user has set this property as a system default, meaning that it should
// take priority over app defaults. If
// SbAccessibilityCaptionSettings.supportsOverride contains true, this value
// should be interpreted as explicitly saying "do not override." If it
// contains false, it is up to the application to intepret any additional
// meaning of this value.
kSbAccessibilityCaptionStateSet,
// This property should take priority over everything but application-level
// overrides, including video caption data. If
// SbAccessibilityCaptionSettings.supportsOverride contains false, then no
// fields of SbAccessibilityCaptionSettings will ever contain this value.
kSbAccessibilityCaptionStateOverride,
} SbAccessibilityCaptionState;
// A group of settings related to system-level closed captioning settings, for
// platforms that expose closed captioning settings.
typedef struct SbAccessibilityCaptionSettings {
SbAccessibilityCaptionColor background_color;
SbAccessibilityCaptionState background_color_state;
SbAccessibilityCaptionOpacityPercentage background_opacity;
SbAccessibilityCaptionState background_opacity_state;
SbAccessibilityCaptionCharacterEdgeStyle character_edge_style;
SbAccessibilityCaptionState character_edge_style_state;
SbAccessibilityCaptionColor font_color;
SbAccessibilityCaptionState font_color_state;
SbAccessibilityCaptionFontFamily font_family;
SbAccessibilityCaptionState font_family_state;
SbAccessibilityCaptionOpacityPercentage font_opacity;
SbAccessibilityCaptionState font_opacity_state;
SbAccessibilityCaptionFontSizePercentage font_size;
SbAccessibilityCaptionState font_size_state;
SbAccessibilityCaptionColor window_color;
SbAccessibilityCaptionState window_color_state;
SbAccessibilityCaptionOpacityPercentage window_opacity;
SbAccessibilityCaptionState window_opacity_state;
// The |is_enabled| attribute determines if the user has chosen to enable
// closed captions on their system.
bool is_enabled;
// Some platforms support enabling or disabling captions, some support reading
// whether they are enabled from the system settings, and others support
// neither. As a result, there are separate checks for getting and setting
// the value that is contained in the |is_enabled| attribute. Modifying the
// attribute via |SbAccessibilitySetCaptionsEnabled| will change the setting
// system-wide. Attemping to read |is_enabled| when the value of
// |supports_is_enabled| is false will always return false. Attemping to set
// |is_enabled| via |SbAccessibilitySetCaptionsEnabled| when the value of
// |supports_set_enabled| is false will fail silently.
bool supports_is_enabled;
bool supports_set_enabled;
// Some platforms may specify that when setting a property, it should override
// data from video streams and application settings (unless the application
// has its own overrides). Depending on whether this attribute contains true
// or false, the values of |SbAccessibilityCaptionState| should be interpreted
// differently.
bool supports_override;
} SbAccessibilityCaptionSettings;
// Get the platform's settings for system-level closed captions. This function
// returns false if |caption_settings| is NULL or if it is not zero-initialized.
//
// |caption_settings|: A pointer to a zero-initialized
// SbAccessibilityTextToSpeechSettings struct.
SB_EXPORT bool SbAccessibilityGetCaptionSettings(
SbAccessibilityCaptionSettings* caption_settings);
// Modifies whether closed captions are enabled at a system level. This
// function returns false if this feature is not supported by the platform, or
// if changing the setting is unsuccessful. This function will modify the
// setting system-wide.
//
// |enabled|: A boolean indicating whether captions should be turned on (true)
// or off (false).
SB_EXPORT bool SbAccessibilitySetCaptionsEnabled(bool enabled);
#endif // SB_HAS(CAPTIONS)
#ifdef __cplusplus
} // extern "C"
#endif
#endif // STARBOARD_ACCESSIBILITY_H_