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一、chrome.system.display

使用 system.display API 查询展示元数据。

权限

system.display

类型

ActiveState

Chrome 117 及更高版本

用于指示系统是否检测到和使用显示屏的枚举。如果系统未检测到显示屏（可能断开连接，或因睡眠模式等原因而被视为断开连接），则显示屏将被视为“非活动状态”。例如，此状态用于在所有显示屏断开连接时保留现有显示屏。

chrome.system.display  |  API  |  Chrome for Developers

二、chrome.system.display c++接口定义：

1、system_display.idl

extensions\common\api\system_display.idl

// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.// Use the <code>system.display</code> API to query display metadata.
namespace system.display {dictionary Bounds {// The x-coordinate of the upper-left corner.long left;// The y-coordinate of the upper-left corner.long top;// The width of the display in pixels.long width;// The height of the display in pixels.long height;};dictionary Insets {// The x-axis distance from the left bound.long left;// The y-axis distance from the top bound.long top;// The x-axis distance from the right bound.long right;// The y-axis distance from the bottom bound.long bottom;};dictionary Point {// The x-coordinate of the point.long x;// The y-coordinate of the point.long y;};dictionary TouchCalibrationPair {// The coordinates of the display point.Point displayPoint;// The coordinates of the touch point corresponding to the display point.Point touchPoint;};dictionary TouchCalibrationPairQuad {// First pair of touch and display point required for touch calibration.TouchCalibrationPair pair1;// Second pair of touch and display point required for touch calibration.TouchCalibrationPair pair2;// Third pair of touch and display point required for touch calibration.TouchCalibrationPair pair3;// Fourth pair of touch and display point required for touch calibration.TouchCalibrationPair pair4;};dictionary DisplayMode {// The display mode width in device independent (user visible) pixels.long width;// The display mode height in device independent (user visible) pixels.long height;// The display mode width in native pixels.long widthInNativePixels;// The display mode height in native pixels.long heightInNativePixels;// The display mode UI scale factor.[deprecated="Use $(ref: displayZoomFactor)"] double? uiScale;// The display mode device scale factor.double deviceScaleFactor;// The display mode refresh rate in hertz.double refreshRate;// True if the mode is the display's native mode.boolean isNative;// True if the display mode is currently selected.boolean isSelected;// True if this mode is interlaced, false if not provided.boolean? isInterlaced;};// Layout position, i.e. edge of parent that the display is attached to.enum LayoutPosition { top, right, bottom, left };dictionary DisplayLayout {// The unique identifier of the display.DOMString id;// The unique identifier of the parent display. Empty if this is the root.DOMString parentId;// The layout position of this display relative to the parent. This will// be ignored for the root.LayoutPosition position;// The offset of the display along the connected edge. 0 indicates that// the topmost or leftmost corners are aligned.long offset;};// EDID extracted parameters. Field description refers to "VESA ENHANCED// EXTENDED DISPLAY IDENTIFICATION DATA STANDARD (Defines EDID Structure// Version 1, Revision 4)" Release A, Revision 2 September 25, 2006.// https://www.vesa.org/vesa-standardsdictionary Edid {// 3 character manufacturer code. See Sec. 3.4.1 page 21. Required in v1.4.DOMString manufacturerId;// 2 byte manufacturer-assigned code, Sec. 3.4.2 page 21. Required in v1.4.DOMString productId;// Year of manufacturer, Sec. 3.4.4 page 22. Required in v1.4.long yearOfManufacture;};// An enum to tell if the display is detected and used by the// system. The display is considered 'inactive', if it is not// detected by the system (maybe disconnected, or considered// disconnected due to sleep mode, etc). This state is used to keep// existing display when the all displays are disconnected, for// example.enum ActiveState { active, inactive };dictionary DisplayUnitInfo {// The unique identifier of the display.DOMString id;// The user-friendly name (e.g. "HP LCD monitor").DOMString name;// NOTE: This is only available to Chrome OS Kiosk apps and Web UI.Edid? edid;// Chrome OS only. Identifier of the display that is being mirrored if// mirroring is enabled, otherwise empty. This will be set for all displays// (including the display being mirrored).DOMString mirroringSourceId;// Chrome OS only. Identifiers of the displays to which the source display// is being mirrored. Empty if no displays are being mirrored. This will be// set to the same value for all displays. This must not include// |mirroringSourceId|.DOMString[] mirroringDestinationIds;// True if this is the primary display.boolean isPrimary;// True if this is an internal display.boolean isInternal;// True if this display is enabled.boolean isEnabled;// Active if the display is detected and used by the system.ActiveState activeState;// True for all displays when in unified desktop mode. See documentation// for $(ref:enableUnifiedDesktop).boolean isUnified;// True when the auto-rotation is allowed. It happens when the device is in// a tablet physical state or kSupportsClamshellAutoRotation is set.// Provided for ChromeOS Settings UI only. TODO(stevenjb): Remove when// Settings switches to a mojo API.[nodoc] boolean? isAutoRotationAllowed;// The number of pixels per inch along the x-axis.double dpiX;// The number of pixels per inch along the y-axis.double dpiY;// The display's clockwise rotation in degrees relative to the vertical// position.// Currently exposed only on ChromeOS. Will be set to 0 on other platforms.// A value of -1 will be interpreted as auto-rotate when the device is in// a physical tablet state.long rotation;// The display's logical bounds.Bounds bounds;// The display's insets within its screen's bounds.// Currently exposed only on ChromeOS. Will be set to empty insets on// other platforms.Insets overscan;// The usable work area of the display within the display bounds. The work// area excludes areas of the display reserved for OS, for example taskbar// and launcher.Bounds workArea;// The list of available display modes. The current mode will have// isSelected=true. Only available on Chrome OS. Will be set to an empty// array on other platforms.DisplayMode[] modes;// True if this display has a touch input device associated with it.boolean hasTouchSupport;// True if this display has an accelerometer associated with it.// Provided for ChromeOS Settings UI only. TODO(stevenjb): Remove when// Settings switches to a mojo API. NOTE: The name of this may change.[nodoc] boolean hasAccelerometerSupport;// A list of zoom factor values that can be set for the display.double[] availableDisplayZoomFactors;// The ratio between the display's current and default zoom.// For example, value 1 is equivalent to 100% zoom, and value 1.5 is// equivalent to 150% zoom.double displayZoomFactor;};dictionary DisplayProperties {// Chrome OS only. If set to true, changes the display mode to unified// desktop (see $(ref:enableUnifiedDesktop) for details). If set to false,// unified desktop mode will be disabled. This is only valid for the// primary display. If provided, mirroringSourceId must not be provided and// other properties will be ignored. This is has no effect if not provided.boolean? isUnified;// Chrome OS only. If set and not empty, enables mirroring for this display// only. Otherwise disables mirroring for all displays. This value should// indicate the id of the source display to mirror, which must not be the// same as the id passed to setDisplayProperties. If set, no other property// may be set.[deprecated="Use $(ref:setMirrorMode)."] DOMString? mirroringSourceId;// If set to true, makes the display primary. No-op if set to false.// Note: If set, the display is considered primary for all other properties// (i.e. $(ref:isUnified) may be set and bounds origin may not).boolean? isPrimary;// If set, sets the display's overscan insets to the provided values. Note// that overscan values may not be negative or larger than a half of the// screen's size. Overscan cannot be changed on the internal monitor.Insets? overscan;// If set, updates the display's rotation.// Legal values are [0, 90, 180, 270]. The rotation is set clockwise,// relative to the display's vertical position.long? rotation;// If set, updates the display's logical bounds origin along the x-axis.// Applied together with $(ref:boundsOriginY). Defaults to the current value// if not set and $(ref:boundsOriginY) is set. Note that when updating the// display origin, some constraints will be applied, so the final bounds// origin may be different than the one set. The final bounds can be// retrieved using $(ref:getInfo). The bounds origin cannot be changed on// the primary display.long? boundsOriginX;// If set, updates the display's logical bounds origin along the y-axis.// See documentation for $(ref:boundsOriginX) parameter.long? boundsOriginY;// If set, updates the display mode to the mode matching this value.// If other parameters are invalid, this will not be applied. If the// display mode is invalid, it will not be applied and an error will be// set, but other properties will still be applied.DisplayMode? displayMode;// If set, updates the zoom associated with the display. This zoom performs// re-layout and repaint thus resulting in a better quality zoom than just// performing a pixel by pixel stretch enlargement.double? displayZoomFactor;};dictionary GetInfoFlags {// If set to true, only a single $(ref:DisplayUnitInfo) will be returned// by $(ref:getInfo) when in unified desktop mode (see// $(ref:enableUnifiedDesktop)). Defaults to false.boolean? singleUnified;};// Mirror mode, i.e. different ways of how a display is mirrored to other// displays.enum MirrorMode {// Specifies the default mode (extended or unified desktop).off,// Specifies that the default source display will be mirrored to all other// displays.normal,// Specifies that the specified source display will be mirrored to the// provided destination displays. All other connected displays will be//  extended.mixed};dictionary MirrorModeInfo {// The mirror mode that should be set.MirrorMode mode;// The id of the mirroring source display. This is only valid for 'mixed'.DOMString? mirroringSourceId;// The ids of the mirroring destination displays. This is only valid for// 'mixed'.DOMString[]? mirroringDestinationIds;};callback DisplayInfoCallback = void (DisplayUnitInfo[] displayInfo);callback DisplayLayoutCallback = void (DisplayLayout[] layouts);callback SetDisplayUnitInfoCallback = void();callback SetDisplayLayoutCallback = void();callback NativeTouchCalibrationCallback = void(boolean success);callback SetMirrorModeCallback = void();interface Functions {// Requests the information for all attached display devices.// |flags|: Options affecting how the information is returned.// |callback|: The callback to invoke with the results.[supportsPromises] static void getInfo(optional GetInfoFlags flags,DisplayInfoCallback callback);// Requests the layout info for all displays.// NOTE: This is only available to Chrome OS Kiosk apps and Web UI.// |callback|: The callback to invoke with the results.[supportsPromises] static void getDisplayLayout(DisplayLayoutCallback callback);// Updates the properties for the display specified by |id|, according to// the information provided in |info|. On failure, $(ref:runtime.lastError)// will be set.// NOTE: This is only available to Chrome OS Kiosk apps and Web UI.// |id|: The display's unique identifier.// |info|: The information about display properties that should be changed.//     A property will be changed only if a new value for it is specified in//     |info|.// |callback|: Empty function called when the function finishes. To find out//     whether the function succeeded, $(ref:runtime.lastError) should be//     queried.[supportsPromises] static void setDisplayProperties(DOMString id,DisplayProperties info,optional SetDisplayUnitInfoCallback callback);// Set the layout for all displays. Any display not included will use the// default layout. If a layout would overlap or be otherwise invalid it// will be adjusted to a valid layout. After layout is resolved, an// onDisplayChanged event will be triggered.// NOTE: This is only available to Chrome OS Kiosk apps and Web UI.// |layouts|: The layout information, required for all displays except//     the primary display.// |callback|: Empty function called when the function finishes. To find out//     whether the function succeeded, $(ref:runtime.lastError) should be//     queried.[supportsPromises] static void setDisplayLayout(DisplayLayout[] layouts,optional SetDisplayLayoutCallback callback);// Enables/disables the unified desktop feature. If enabled while mirroring// is active, the desktop mode will not change until mirroring is turned// off. Otherwise, the desktop mode will switch to unified immediately.// NOTE: This is only available to Chrome OS Kiosk apps and Web UI.// |enabled|: True if unified desktop should be enabled.static void enableUnifiedDesktop(boolean enabled);// Starts overscan calibration for a display. This will show an overlay// on the screen indicating the current overscan insets. If overscan// calibration for display |id| is in progress this will reset calibration.// |id|: The display's unique identifier.static void overscanCalibrationStart(DOMString id);// Adjusts the current overscan insets for a display. Typically this should// either move the display along an axis (e.g. left+right have the same// value) or scale it along an axis (e.g. top+bottom have opposite values).// Each Adjust call is cumulative with previous calls since Start.// |id|: The display's unique identifier.// |delta|: The amount to change the overscan insets.static void overscanCalibrationAdjust(DOMString id, Insets delta);// Resets the overscan insets for a display to the last saved value (i.e// before Start was called).// |id|: The display's unique identifier.static void overscanCalibrationReset(DOMString id);// Complete overscan adjustments for a display  by saving the current values// and hiding the overlay.// |id|: The display's unique identifier.static void overscanCalibrationComplete(DOMString id);// Displays the native touch calibration UX for the display with |id| as// display id. This will show an overlay on the screen with required// instructions on how to proceed. The callback will be invoked in case of// successful calibration only. If the calibration fails, this will throw an// error.// |id|: The display's unique identifier.// |callback|: Optional callback to inform the caller that the touch//      calibration has ended. The argument of the callback informs if the//      calibration was a success or not.[supportsPromises] static void showNativeTouchCalibration(DOMString id,optional NativeTouchCalibrationCallback callback);// Starts custom touch calibration for a display. This should be called when// using a custom UX for collecting calibration data. If another touch// calibration is already in progress this will throw an error.// |id|: The display's unique identifier.static void startCustomTouchCalibration(DOMString id);// Sets the touch calibration pairs for a display. These |pairs| would be// used to calibrate the touch screen for display with |id| called in// startCustomTouchCalibration(). Always call |startCustomTouchCalibration|// before calling this method. If another touch calibration is already in// progress this will throw an error.// |pairs|: The pairs of point used to calibrate the display.// |bounds|: Bounds of the display when the touch calibration was performed.//     |bounds.left| and |bounds.top| values are ignored.static void completeCustomTouchCalibration(TouchCalibrationPairQuad pairs,Bounds bounds);// Resets the touch calibration for the display and brings it back to its// default state by clearing any touch calibration data associated with the// display.// |id|: The display's unique identifier.static void clearTouchCalibration(DOMString id);// Sets the display mode to the specified mirror mode. Each call resets the// state from previous calls. Calling setDisplayProperties() will fail for// the mirroring destination displays.// NOTE: This is only available to Chrome OS Kiosk apps and Web UI.// |info|: The information of the mirror mode that should be applied to the//     display mode.// |callback|: Empty function called when the function finishes. To find out//     whether the function succeeded, $(ref:runtime.lastError) should be//     queried.[supportsPromises] static void setMirrorMode(MirrorModeInfo info,optional SetMirrorModeCallback callback);};interface Events {// Fired when anything changes to the display configuration.static void onDisplayChanged();};
};

2、system_display.idl生成c++文件：

out\Debug\gen\extensions\common\api\system_display.h

out\Debug\gen\extensions\common\api\system_display.cc

3、chrome.system.display api接口定义c++:

extensions\browser\api\system_display\system_display_api.h

extensions\browser\api\system_display\system_display_api.cc

namespace extensions {class SystemDisplayFunction : public ExtensionFunction {public:static const char kApiNotAvailableError[];protected:~SystemDisplayFunction() override = default;bool PreRunValidation(std::string* error) override;
};class SystemDisplayCrOSRestrictedFunction : public SystemDisplayFunction {public:static const char kCrosOnlyError[];static const char kKioskOnlyError[];protected:~SystemDisplayCrOSRestrictedFunction() override = default;bool PreRunValidation(std::string* error) override;// Returns true if this function should be restricted to kiosk-mode apps and// webui. The default is true.virtual bool ShouldRestrictToKioskAndWebUI();
};// This function inherits from SystemDisplayFunction because, unlike the
// rest of this API, it's available on all platforms.
class SystemDisplayGetInfoFunction : public SystemDisplayFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.getInfo", SYSTEM_DISPLAY_GETINFO)protected:~SystemDisplayGetInfoFunction() override = default;ResponseAction Run() override;void Response(std::vector<api::system_display::DisplayUnitInfo> all_displays_info);
};class SystemDisplayGetDisplayLayoutFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.getDisplayLayout",SYSTEM_DISPLAY_GETDISPLAYLAYOUT)protected:~SystemDisplayGetDisplayLayoutFunction() override = default;ResponseAction Run() override;bool ShouldRestrictToKioskAndWebUI() override;void Response(std::vector<api::system_display::DisplayLayout> display_layout);
};class SystemDisplaySetDisplayPropertiesFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.setDisplayProperties",SYSTEM_DISPLAY_SETDISPLAYPROPERTIES)protected:~SystemDisplaySetDisplayPropertiesFunction() override = default;ResponseAction Run() override;void Response(std::optional<std::string> error);
};class SystemDisplaySetDisplayLayoutFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.setDisplayLayout",SYSTEM_DISPLAY_SETDISPLAYLAYOUT)protected:~SystemDisplaySetDisplayLayoutFunction() override = default;ResponseAction Run() override;void Response(std::optional<std::string> error);
};class SystemDisplayEnableUnifiedDesktopFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.enableUnifiedDesktop",SYSTEM_DISPLAY_ENABLEUNIFIEDDESKTOP)protected:~SystemDisplayEnableUnifiedDesktopFunction() override = default;ResponseAction Run() override;
};class SystemDisplayOverscanCalibrationStartFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.overscanCalibrationStart",SYSTEM_DISPLAY_OVERSCANCALIBRATIONSTART)protected:~SystemDisplayOverscanCalibrationStartFunction() override = default;ResponseAction Run() override;
};class SystemDisplayOverscanCalibrationAdjustFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.overscanCalibrationAdjust",SYSTEM_DISPLAY_OVERSCANCALIBRATIONADJUST)protected:~SystemDisplayOverscanCalibrationAdjustFunction() override = default;ResponseAction Run() override;
};class SystemDisplayOverscanCalibrationResetFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.overscanCalibrationReset",SYSTEM_DISPLAY_OVERSCANCALIBRATIONRESET)protected:~SystemDisplayOverscanCalibrationResetFunction() override = default;ResponseAction Run() override;
};class SystemDisplayOverscanCalibrationCompleteFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.overscanCalibrationComplete",SYSTEM_DISPLAY_OVERSCANCALIBRATIONCOMPLETE)protected:~SystemDisplayOverscanCalibrationCompleteFunction() override = default;ResponseAction Run() override;
};class SystemDisplayShowNativeTouchCalibrationFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.showNativeTouchCalibration",SYSTEM_DISPLAY_SHOWNATIVETOUCHCALIBRATION)protected:~SystemDisplayShowNativeTouchCalibrationFunction() override = default;ResponseAction Run() override;void OnCalibrationComplete(std::optional<std::string> error);
};class SystemDisplayStartCustomTouchCalibrationFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.startCustomTouchCalibration",SYSTEM_DISPLAY_STARTCUSTOMTOUCHCALIBRATION)protected:~SystemDisplayStartCustomTouchCalibrationFunction() override = default;ResponseAction Run() override;
};class SystemDisplayCompleteCustomTouchCalibrationFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.completeCustomTouchCalibration",SYSTEM_DISPLAY_COMPLETECUSTOMTOUCHCALIBRATION)protected:~SystemDisplayCompleteCustomTouchCalibrationFunction() override = default;ResponseAction Run() override;
};class SystemDisplayClearTouchCalibrationFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.clearTouchCalibration",SYSTEM_DISPLAY_CLEARTOUCHCALIBRATION)protected:~SystemDisplayClearTouchCalibrationFunction() override = default;ResponseAction Run() override;
};class SystemDisplaySetMirrorModeFunction: public SystemDisplayCrOSRestrictedFunction {public:DECLARE_EXTENSION_FUNCTION("system.display.setMirrorMode",SYSTEM_DISPLAY_SETMIRRORMODE)protected:~SystemDisplaySetMirrorModeFunction() override = default;ResponseAction Run() override;void Response(std::optional<std::string> error);
};}  // namespace extensions