1 ## 7.1\. Display and Graphics 2 3 Android includes facilities that automatically adjust application assets and UI 4 layouts appropriately for the device to ensure that third-party applications 5 run well on a [variety of hardware configurations](http://developer.android.com/guide/practices/screens_support.html). 6 Devices MUST properly implement these APIs and behaviors, as detailed in this 7 section. 8 9 The units referenced by the requirements in this section are defined as follows: 10 11 * **physical diagonal size**. The distance in inches between two opposing 12 corners of the illuminated portion of the display. 13 * **dots per inch (dpi)**. The number of pixels encompassed by a linear 14 horizontal or vertical span of 1. Where dpi values are listed, both horizontal 15 and vertical dpi must fall within the range. 16 * **aspect ratio**. The ratio of the pixels of the longer dimension to the 17 shorter dimension of the screen. For example, a display of 480x854 pixels would 18 be 854/480 = 1.779, or roughly 16:9. 19 * **density-independent pixel (dp)**. The virtual pixel unit normalized to a 20 160 dpi screen, calculated as: pixels = dps * (density/160). 21 22 ### 7.1.1\. Screen Configuration 23 24 #### 7.1.1.1\. Screen Size 25 26 * [H-0-1] Handheld device implementations MUST have a screen at least 2.5 27 inches in physical diagonal size. 28 29 * [A-0-1] Android Automotive devices MUST have a screen at least 6 inches 30 in physical diagonal size. 31 32 * [A-0-2] Android Automotive devices MUST have a screen size layout of 33 at least 750 dp x 480 dp. 34 35 * [W-0-1] Android Watch device implementations MUST have a screen with the 36 physical diagonal size in the range from 1.1 to 2.5 inches. 37 38 The Android UI framework supports a variety of different logical screen layout 39 sizes, and allows applications to query the current configuration's screen 40 layout size via `Configuration.screenLayout` with the `SCREENLAYOUT_SIZE_MASK` 41 and `Configuration.smallestScreenWidthDp`. 42 43 * [C-0-1] Device implementations MUST report the correct layout size for the 44 `Configuration.screenLayout` as defined in the Android SDK documentation. 45 Specifically, device implementations MUST report the correct logical 46 density-independent pixel (dp) screen dimensions as below: 47 48 * Devices with the `Configuration.uiMode` set as any value other than 49 UI_MODE_TYPE_WATCH, and reporting a `small` size for the 50 `Configuration.screenLayout`, MUST have at least 426 dp x 320 dp. 51 * Devices reporting a `normal` size for the `Configuration.screenLayout`, 52 MUST have at least 480 dp x 320 dp. 53 * Devices reporting a `large` size for the `Configuration.screenLayout`, 54 MUST have at least 640 dp x 480 dp. 55 * Devices reporting a `xlarge` size for the `Configuration.screenLayout`, 56 MUST have at least 960 dp x 720 dp. 57 58 * [C-0-2] Device implementations MUST correctly honor applications' stated 59 support for screen sizes through the [<`supports-screens`>]( 60 https://developer.android.com/guide/topics/manifest/supports-screens-element.html) 61 attribute in the AndroidManifest.xml, as described 62 in the Android SDK documentation. 63 64 #### 7.1.1.2\. Screen Aspect Ratio 65 66 While there is no restriction to the screen aspect ratio value of the physical 67 screen display, the screen aspect ratio of the logical display that third-party 68 apps are rendered within, as can be derived from the height and width values 69 reported through the [`view.Display`]( 70 https://developer.android.com/reference/android/view/Display.html) 71 APIs and [Configuration]( 72 https://developer.android.com/reference/android/content/res/Configuration.html) 73 API, MUST meet the following requirements: 74 75 * [C-0-1] Device implementations with the `Configuration.uiMode` set as 76 `UI_MODE_TYPE_NORMAL` MUST have an aspect ratio value between 1.3333 (4:3) 77 and 1.86 (roughly 16:9), unless the app can be deemed as ready to be 78 stretched longer by meeting one of the following conditions: 79 80 * The app has declared that it supports a larger screen aspect ratio 81 through the [`android.max_aspect`]( 82 https://developer.android.com/guide/practices/screens_support.html#MaxAspectRatio) 83 metadata value. 84 * The app declares it is resizeable via the [android:resizeableActivity]( 85 https://developer.android.com/guide/topics/ui/multi-window.html#configuring) 86 attribute. 87 * The app is targeting API level 26 or higher and does not declare a 88 [`android:MaxAspectRatio`]( 89 https://developer.android.com/reference/android/R.attr.html#maxAspectRatio) 90 that would restrict the allowed aspect ratio. 91 92 93 * [C-0-2] Device implementations with the `Configuration.uiMode` set as 94 `UI_MODE_TYPE_WATCH` MUST have an aspect ratio value set as 1.0 (1:1). 95 96 #### 7.1.1.3\. Screen Density 97 98 The Android UI framework defines a set of standard logical densities to help 99 application developers target application resources. 100 101 * [C-0-1] By default, device implementations MUST report only one of the 102 following logical Android framework densities through the 103 [DENSITY_DEVICE_STABLE]( 104 https://developer.android.com/reference/android/util/DisplayMetrics.html#DENSITY_DEVICE_STABLE) 105 API and this value MUST NOT change at any time; however, the device MAY report 106 a different arbitrary density according to the display configuration changes 107 made by the user (for example, display size) set after initial boot. 108 109 * 120 dpi (ldpi) 110 * 160 dpi (mdpi) 111 * 213 dpi (tvdpi) 112 * 240 dpi (hdpi) 113 * 260 dpi (260dpi) 114 * 280 dpi (280dpi) 115 * 300 dpi (300dpi) 116 * 320 dpi (xhdpi) 117 * 340 dpi (340dpi) 118 * 360 dpi (360dpi) 119 * 400 dpi (400dpi) 120 * 420 dpi (420dpi) 121 * 480 dpi (xxhdpi) 122 * 560 dpi (560dpi) 123 * 640 dpi (xxxhdpi) 124 125 * Device implementations SHOULD define the standard Android framework density 126 that is numerically closest to the physical density of the screen, unless that 127 logical density pushes the reported screen size below the minimum supported. If 128 the standard Android framework density that is numerically closest to the 129 physical density results in a screen size that is smaller than the smallest 130 supported compatible screen size (320 dp width), device implementations SHOULD 131 report the next lowest standard Android framework density. 132 133 * [H-SR] Device implementations are STRONGLY RECOMMENDED to provide users an 134 affordance to change the display size. 135 136 If there is an affordance to change the display size of the device: 137 138 * [C-1-1] The display size MUST NOT be scaled any larger than 1.5 times the native density or 139 produce an effective minimum screen dimension smaller than 320dp (equivalent 140 to resource qualifier sw320dp), whichever comes first. 141 * [C-1-2] Display size MUST NOT be scaled any smaller than 0.85 times the native density. 142 * To ensure good usability and consistent font sizes, it is RECOMMENDED that the 143 following scaling of Native Display options be provided (while complying with the limits 144 specified above) 145 * Small: 0.85x 146 * Default: 1x (Native display scale) 147 * Large: 1.15x 148 * Larger: 1.3x 149 * Largest 1.45x 150 151 ### 7.1.2\. Display Metrics 152 153 If device implementations include a screen or video output, they: 154 155 * [C-1-1] MUST report correct values for all display metrics defined in the 156 [`android.util.DisplayMetrics`]( 157 https://developer.android.com/reference/android/util/DisplayMetrics.html) API. 158 159 If device implementations does not include an embedded screen or video output, 160 they: 161 162 * [C-2-1] MUST report reasonable values for all display metrics defined in 163 the [`android.util.DisplayMetrics`]( 164 https://developer.android.com/reference/android/util/DisplayMetrics.html) API 165 for the emulated default `view.Display`. 166 167 168 169 ### 7.1.3\. Screen Orientation 170 171 Device implementations: 172 173 * [C-0-1] MUST report which screen orientations they support 174 (`android.hardware.screen.portrait` and/or 175 `android.hardware.screen.landscape`) and MUST report at least one supported 176 orientation. For example, a device with a fixed orientation landscape 177 screen, such as a television or laptop, SHOULD only 178 report `android.hardware.screen.landscape`. 179 * [C-0-2] MUST report the correct value for the devices current 180 orientation, whenever queried via the 181 `android.content.res.Configuration.orientation`, 182 `android.view.Display.getOrientation()`, or other APIs. 183 184 If device implementations support both screen orientations, they: 185 186 * [C-1-1] MUST support dynamic orientation by applications to either portrait or landscape screen 187 orientation. That is, the device must respect the applications request for a specific screen 188 orientation. 189 * [C-1-2] MUST NOT change the reported screen size or density when changing orientation. 190 * MAY select either portrait or landscape orientation as the default. 191 192 193 ### 7.1.4\. 2D and 3D Graphics Acceleration 194 195 #### 7.1.4.1 OpenGL ES 196 197 Device implementations: 198 199 * [C-0-1] MUST correctly identify the supported OpenGL ES versions (1.1, 2.0, 200 3.0, 3.1, 3.2) through the managed APIs (such as via the 201 `GLES10.getString()` method) and the native APIs. 202 * [C-0-2] MUST include the support for all the corresponding managed APIs and 203 native APIs for every OpenGL ES versions they identified to support. 204 205 If device implementations include a screen or video output, they: 206 207 * [C-1-1] MUST support both OpenGL ES 1.0 and 2.0, as embodied and detailed 208 in the [Android SDK documentation]( 209 https://developer.android.com/guide/topics/graphics/opengl.html). 210 * [SR] are STRONGLY RECOMMENDED to support OpenGL ES 3.0. 211 * SHOULD support OpenGL ES 3.1 or 3.2. 212 213 If device implementations support any of the OpenGL ES versions, they: 214 215 * [C-2-1] MUST report via the OpenGL ES managed APIs and native APIs any 216 other OpenGL ES extensions they have implemented, and conversely MUST 217 NOT report extension strings that they do not support. 218 * [C-2-2] MUST support the `EGL_KHR_image`, `EGL_KHR_image_base`, 219 `EGL_ANDROID_image_native_buffer`, `EGL_ANDROID_get_native_client_buffer`, 220 `EGL_KHR_wait_sync`, `EGL_KHR_get_all_proc_addresses`, 221 `EGL_ANDROID_presentation_time`, `EGL_KHR_swap_buffers_with_damage` and 222 `EGL_ANDROID_recordable` extensions. 223 * [SR] are STRONGLY RECOMMENDED to support EGL_KHR_partial_update. 224 * SHOULD accurately report via the `getString()` method, any texture 225 compression format that they support, which is typically vendor-specific. 226 227 If device implementations declare support for OpenGL ES 3.0, 3.1, or 3.2, they: 228 229 * [C-3-1] MUST export the corresponding function symbols for these version in 230 addition to the OpenGL ES 2.0 function symbols in the libGLESv2.so library. 231 232 If device implementations support OpenGL ES 3.2, they: 233 234 * [C-4-1] MUST support the OpenGL ES Android Extension Pack in its entirety. 235 236 If device implementations support the OpenGL ES [Android Extension Pack]( 237 https://developer.android.com/reference/android/opengl/GLES31Ext.html) in its 238 entirety, they: 239 240 * [C-5-1] MUST identify the support through the `android.hardware.opengles.aep` 241 feature flag. 242 243 If device implementations expose support for the `EGL_KHR_mutable_render_buffer` 244 extension, they: 245 246 * [C-6-1] MUST also support the `EGL_ANDROID_front_buffer_auto_refresh` 247 extension. 248 249 #### 7.1.4.2 Vulkan 250 251 Android includes support for [Vulkan]( 252 https://www.khronos.org/registry/vulkan/specs/1.0-wsi&lowbarextensions/xhtml/vkspec.html) 253 , a low-overhead, cross-platform API for high-performance 3D graphics. 254 255 If device implementations support OpenGL ES 3.0 or 3.1, they: 256 257 * [SR] Are STRONGLY RECOMMENDED to include support for Vulkan 1.0 . 258 259 If device implementations include a screen or video output, they: 260 261 * SHOULD include support for Vulkan 1.0. 262 263 Device implementations, if including support for Vulkan 1.0: 264 265 * [C-1-1] MUST report the correct integer value with the 266 `android.hardware.vulkan.level` and `android.hardware.vulkan.version` 267 feature flags. 268 * [C-1-2] MUST enumarate, at least one `VkPhysicalDevice` for the Vulkan 269 native API [`vkEnumeratePhysicalDevices()`]( 270 https://www.khronos.org/registry/vulkan/specs/1.0/man/html/vkEnumeratePhysicalDevices.html) 271 . 272 * [C-1-3] MUST fully implement the Vulkan 1.0 APIs for each enumerated 273 `VkPhysicalDevice`. 274 * [C-1-4] MUST enumerate layers, contained in native libraries named as 275 `libVkLayer*.so` in the application packages native library directory, 276 through the Vulkan native APIs [`vkEnumerateInstanceLayerProperties()`]( 277 https://www.khronos.org/registry/vulkan/specs/1.0/man/html/vkEnumerateInstanceLayerProperties.html) 278 and [`vkEnumerateDeviceLayerProperties()`]( 279 https://www.khronos.org/registry/vulkan/specs/1.0/man/html/vkEnumerateDeviceLayerProperties.html) 280 . 281 * [C-1-5] MUST NOT enumerate layers provided by libraries outside of the 282 application package, or provide other ways of tracing or intercepting the 283 Vulkan API, unless the application has the `android:debuggable` attribute 284 set as `true`. 285 * [C-1-6] MUST report all extension strings that they do support via the 286 Vulkan native APIs , and conversely MUST NOT report extension strings 287 that they do not correctly support. 288 289 Device implementations, if not including support for Vulkan 1.0: 290 291 * [C-2-1] MUST NOT declare any of the Vulkan feature flags (e.g. 292 `android.hardware.vulkan.level`, `android.hardware.vulkan.version`). 293 * [C-2-2] MUST NOT enumarate any `VkPhysicalDevice` for the Vulkan native API 294 `vkEnumeratePhysicalDevices()`. 295 296 #### 7.1.4.3 RenderScript 297 298 * [C-0-1] Device implementations MUST support [Android RenderScript]( 299 http://developer.android.com/guide/topics/renderscript/), as detailed 300 in the Android SDK documentation. 301 302 #### 7.1.4.4 2D Graphics Acceleration 303 304 Android includes a mechanism for applications to declare that they want to 305 enable hardware acceleration for 2D graphics at the Application, Activity, 306 Window, or View level through the use of a manifest tag 307 [android:hardwareAccelerated]( 308 http://developer.android.com/guide/topics/graphics/hardware-accel.html) 309 or direct API calls. 310 311 Device implementations: 312 313 * [C-0-1] MUST enable hardware acceleration by default, and MUST 314 disable hardware acceleration if the developer so requests by setting 315 android:hardwareAccelerated="false or disabling hardware acceleration 316 directly through the Android View APIs. 317 * [C-0-2] MUST exhibit behavior consistent with the 318 Android SDK documentation on [hardware acceleration]( 319 http://developer.android.com/guide/topics/graphics/hardware-accel.html). 320 321 Android includes a TextureView object that lets developers directly integrate 322 hardware-accelerated OpenGL ES textures as rendering targets in a UI hierarchy. 323 324 * [C-0-3] MUST support the TextureView API, and MUST exhibit 325 consistent behavior with the upstream Android implementation. 326 327 #### 7.1.4.5 Wide-gamut Displays 328 329 If device implementations claim support for wide-gamut displays through 330 [`Display.isWideColorGamut()` 331 ](https://developer.android.com/reference/android/view/Display.html#isWideColorGamut%28%29) 332 , they: 333 334 * [C-1-1] MUST have a color-calibrated display. 335 * [C-1-2] MUST have a display whose gamut covers the sRGB color gamut entirely 336 in CIE 1931 xyY space. 337 * [C-1-3] MUST have a display whose gamut has an area of at least 90% of NTSC 338 1953 in CIE 1931 xyY space. 339 * [C-1-4] MUST support OpenGL ES 3.0, 3.1, or 3.2 and report it properly. 340 * [C-1-5] MUST advertise support for the `EGL_KHR_no_config_context`, 341 `EGL_EXT_pixel_format_float`,`EGL_KHR_gl_colorspace`, 342 `EGL_EXT_colorspace_scrgb_linear`, and `EGL_GL_colorspace_display_p3` 343 extensions. 344 * [SR] Are STRONGLY RECOMMENDED to support `GL_EXT_sRGB`. 345 346 Conversely, if device implementations do not support wide-gamut displays, they: 347 348 * [C-2-1] SHOULD cover 100% or more of sRGB in CIE 1931 xyY space, although 349 the screen color gamut is undefined. 350 351 ### 7.1.5\. Legacy Application Compatibility Mode 352 353 Android specifies a compatibility mode in which the framework operates in a 354 'normal' screen size equivalent (320dp width) mode for the benefit of legacy 355 applications not developed for old versions of Android that pre-date 356 screen-size independence. 357 358 * [H-0-1] Handheld device implementations MUST include support 359 for legacy application compatibility mode as implemented by the upstream 360 Android open source code. That is, device implementations MUST NOT alter the 361 triggers or thresholds at which compatibility mode is activated, and MUST 362 NOT alter the behavior of the compatibility mode itself. 363 364 ### 7.1.6\. Screen Technology 365 366 The Android platform includes APIs that allow applications to render rich 367 graphics to the display. Devices MUST support all of these APIs as defined by 368 the Android SDK unless specifically allowed in this document. 369 370 Device implementations: 371 372 * [C-0-1] MUST support displays capable of rendering 16-bit color graphics. 373 * SHOULD support displays capable of 24-bit color graphics. 374 * [C-0-2] MUST support displays capable of rendering animations. 375 * [C-0-3] MUST use the display technology that have a pixel aspect ratio (PAR) 376 between 0.9 and 1.15\. That is, the pixel aspect ratio MUST be near square 377 (1.0) with a 10 ~ 15% tolerance. 378 379 ### 7.1.7\. Secondary Displays 380 381 Android includes support for secondary display to enable media sharing 382 capabilities and developer APIs for accessing external displays. 383 384 If device implementations support an external display either via a wired, 385 wireless, or an embedded additional display connection, they: 386 387 * [C-1-1] MUST implement the [`DisplayManager`]( 388 https://developer.android.com/reference/android/hardware/display/DisplayManager.html) 389 system service and API as described in the Android SDK documentation.
