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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ANDROID_INCLUDE_HARDWARE_HWCOMPOSER_H
     18 #define ANDROID_INCLUDE_HARDWARE_HWCOMPOSER_H
     19 
     20 #include <stdint.h>
     21 #include <sys/cdefs.h>
     22 
     23 #include <hardware/gralloc.h>
     24 #include <hardware/hardware.h>
     25 #include <cutils/native_handle.h>
     26 
     27 __BEGIN_DECLS
     28 
     29 /*****************************************************************************/
     30 
     31 #define HWC_API_VERSION 1
     32 
     33 /**
     34  * The id of this module
     35  */
     36 #define HWC_HARDWARE_MODULE_ID "hwcomposer"
     37 
     38 /**
     39  * Name of the sensors device to open
     40  */
     41 #define HWC_HARDWARE_COMPOSER   "composer"
     42 
     43 
     44 enum {
     45     /* hwc_composer_device_t::set failed in EGL */
     46     HWC_EGL_ERROR = -1
     47 };
     48 
     49 /*
     50  * hwc_layer_t::hints values
     51  * Hints are set by the HAL and read by SurfaceFlinger
     52  */
     53 enum {
     54     /*
     55      * HWC can set the HWC_HINT_TRIPLE_BUFFER hint to indicate to SurfaceFlinger
     56      * that it should triple buffer this layer. Typically HWC does this when
     57      * the layer will be unavailable for use for an extended period of time,
     58      * e.g. if the display will be fetching data directly from the layer and
     59      * the layer can not be modified until after the next set().
     60      */
     61     HWC_HINT_TRIPLE_BUFFER  = 0x00000001,
     62 
     63     /*
     64      * HWC sets HWC_HINT_CLEAR_FB to tell SurfaceFlinger that it should clear the
     65      * framebuffer with transparent pixels where this layer would be.
     66      * SurfaceFlinger will only honor this flag when the layer has no blending
     67      *
     68      */
     69     HWC_HINT_CLEAR_FB       = 0x00000002
     70 };
     71 
     72 /*
     73  * hwc_layer_t::flags values
     74  * Flags are set by SurfaceFlinger and read by the HAL
     75  */
     76 enum {
     77     /*
     78      * HWC_SKIP_LAYER is set by SurfaceFlnger to indicate that the HAL
     79      * shall not consider this layer for composition as it will be handled
     80      * by SurfaceFlinger (just as if compositionType was set to HWC_OVERLAY).
     81      */
     82     HWC_SKIP_LAYER = 0x00000001,
     83 };
     84 
     85 /*
     86  * hwc_layer_t::compositionType values
     87  */
     88 enum {
     89     /* this layer is to be drawn into the framebuffer by SurfaceFlinger */
     90     HWC_FRAMEBUFFER = 0,
     91 
     92     /* this layer will be handled in the HWC */
     93     HWC_OVERLAY = 1,
     94 };
     95 
     96 /*
     97  * hwc_layer_t::blending values
     98  */
     99 enum {
    100     /* no blending */
    101     HWC_BLENDING_NONE     = 0x0100,
    102 
    103     /* ONE / ONE_MINUS_SRC_ALPHA */
    104     HWC_BLENDING_PREMULT  = 0x0105,
    105 
    106     /* SRC_ALPHA / ONE_MINUS_SRC_ALPHA */
    107     HWC_BLENDING_COVERAGE = 0x0405
    108 };
    109 
    110 /*
    111  * hwc_layer_t::transform values
    112  */
    113 enum {
    114     /* flip source image horizontally */
    115     HWC_TRANSFORM_FLIP_H = HAL_TRANSFORM_FLIP_H,
    116     /* flip source image vertically */
    117     HWC_TRANSFORM_FLIP_V = HAL_TRANSFORM_FLIP_V,
    118     /* rotate source image 90 degrees clock-wise */
    119     HWC_TRANSFORM_ROT_90 = HAL_TRANSFORM_ROT_90,
    120     /* rotate source image 180 degrees */
    121     HWC_TRANSFORM_ROT_180 = HAL_TRANSFORM_ROT_180,
    122     /* rotate source image 270 degrees clock-wise */
    123     HWC_TRANSFORM_ROT_270 = HAL_TRANSFORM_ROT_270,
    124 };
    125 
    126 typedef struct hwc_rect {
    127     int left;
    128     int top;
    129     int right;
    130     int bottom;
    131 } hwc_rect_t;
    132 
    133 typedef struct hwc_region {
    134     size_t numRects;
    135     hwc_rect_t const* rects;
    136 } hwc_region_t;
    137 
    138 typedef struct hwc_layer {
    139     /*
    140      * initially set to HWC_FRAMEBUFFER, indicates the layer will
    141      * be drawn into the framebuffer using OpenGL ES.
    142      * The HWC can toggle this value to HWC_OVERLAY, to indicate
    143      * it will handle the layer.
    144      */
    145     int32_t compositionType;
    146 
    147     /* see hwc_layer_t::hints above */
    148     uint32_t hints;
    149 
    150     /* see hwc_layer_t::flags above */
    151     uint32_t flags;
    152 
    153     /* handle of buffer to compose. this handle is guaranteed to have been
    154      * allocated with gralloc */
    155     buffer_handle_t handle;
    156 
    157     /* transformation to apply to the buffer during composition */
    158     uint32_t transform;
    159 
    160     /* blending to apply during composition */
    161     int32_t blending;
    162 
    163     /* area of the source to consider, the origin is the top-left corner of
    164      * the buffer */
    165     hwc_rect_t sourceCrop;
    166 
    167     /* where to composite the sourceCrop onto the display. The sourceCrop
    168      * is scaled using linear filtering to the displayFrame. The origin is the
    169      * top-left corner of the screen.
    170      */
    171     hwc_rect_t displayFrame;
    172 
    173     /* visible region in screen space. The origin is the
    174      * top-left corner of the screen.
    175      * The visible region INCLUDES areas overlapped by a translucent layer.
    176      */
    177     hwc_region_t visibleRegionScreen;
    178 } hwc_layer_t;
    179 
    180 
    181 /*
    182  * hwc_layer_list_t::flags values
    183  */
    184 enum {
    185     /*
    186      * HWC_GEOMETRY_CHANGED is set by SurfaceFlinger to indicate that the list
    187      * passed to (*prepare)() has changed by more than just the buffer handles.
    188      */
    189     HWC_GEOMETRY_CHANGED = 0x00000001,
    190 };
    191 
    192 /*
    193  * List of layers.
    194  * The handle members of hwLayers elements must be unique.
    195  */
    196 typedef struct hwc_layer_list {
    197     uint32_t flags;
    198     size_t numHwLayers;
    199     hwc_layer_t hwLayers[0];
    200 } hwc_layer_list_t;
    201 
    202 /* This represents a display, typically an EGLDisplay object */
    203 typedef void* hwc_display_t;
    204 
    205 /* This represents a surface, typically an EGLSurface object  */
    206 typedef void* hwc_surface_t;
    207 
    208 
    209 /* see hwc_composer_device::registerProcs()
    210  * Any of the callbacks can be NULL, in which case the corresponding
    211  * functionality is not supported.
    212  */
    213 typedef struct hwc_procs {
    214     /*
    215      * (*invalidate)() triggers a screen refresh, in particular prepare and set
    216      * will be called shortly after this call is made. Note that there is
    217      * NO GUARANTEE that the screen refresh will happen after invalidate()
    218      * returns (in particular, it could happen before).
    219      * invalidate() is GUARANTEED TO NOT CALL BACK into the h/w composer HAL and
    220      * it is safe to call invalidate() from any of hwc_composer_device
    221      * hooks, unless noted otherwise.
    222      */
    223     void (*invalidate)(struct hwc_procs* procs);
    224 } hwc_procs_t;
    225 
    226 
    227 /*****************************************************************************/
    228 
    229 typedef struct hwc_module {
    230     struct hw_module_t common;
    231 } hwc_module_t;
    232 
    233 
    234 typedef struct hwc_composer_device {
    235     struct hw_device_t common;
    236 
    237     /*
    238      * (*prepare)() is called for each frame before composition and is used by
    239      * SurfaceFlinger to determine what composition steps the HWC can handle.
    240      *
    241      * (*prepare)() can be called more than once, the last call prevails.
    242      *
    243      * The HWC responds by setting the compositionType field to either
    244      * HWC_FRAMEBUFFER or HWC_OVERLAY. In the former case, the composition for
    245      * this layer is handled by SurfaceFlinger with OpenGL ES, in the later
    246      * case, the HWC will have to handle this layer's composition.
    247      *
    248      * (*prepare)() is called with HWC_GEOMETRY_CHANGED to indicate that the
    249      * list's geometry has changed, that is, when more than just the buffer's
    250      * handles have been updated. Typically this happens (but is not limited to)
    251      * when a window is added, removed, resized or moved.
    252      *
    253      * a NULL list parameter or a numHwLayers of zero indicates that the
    254      * entire composition will be handled by SurfaceFlinger with OpenGL ES.
    255      *
    256      * returns: 0 on success. An negative error code on error. If an error is
    257      * returned, SurfaceFlinger will assume that none of the layer will be
    258      * handled by the HWC.
    259      */
    260     int (*prepare)(struct hwc_composer_device *dev, hwc_layer_list_t* list);
    261 
    262 
    263     /*
    264      * (*set)() is used in place of eglSwapBuffers(), and assumes the same
    265      * functionality, except it also commits the work list atomically with
    266      * the actual eglSwapBuffers().
    267      *
    268      * The list parameter is guaranteed to be the same as the one returned
    269      * from the last call to (*prepare)().
    270      *
    271      * When this call returns the caller assumes that:
    272      *
    273      * - the display will be updated in the near future with the content
    274      *   of the work list, without artifacts during the transition from the
    275      *   previous frame.
    276      *
    277      * - all objects are available for immediate access or destruction, in
    278      *   particular, hwc_region_t::rects data and hwc_layer_t::layer's buffer.
    279      *   Note that this means that immediately accessing (potentially from a
    280      *   different process) a buffer used in this call will not result in
    281      *   screen corruption, the driver must apply proper synchronization or
    282      *   scheduling (eg: block the caller, such as gralloc_module_t::lock(),
    283      *   OpenGL ES, Camera, Codecs, etc..., or schedule the caller's work
    284      *   after the buffer is freed from the actual composition).
    285      *
    286      * a NULL list parameter or a numHwLayers of zero indicates that the
    287      * entire composition has been handled by SurfaceFlinger with OpenGL ES.
    288      * In this case, (*set)() behaves just like eglSwapBuffers().
    289      *
    290      * dpy, sur, and list are set to NULL to indicate that the screen is
    291      * turning off. This happens WITHOUT prepare() being called first.
    292      * This is a good time to free h/w resources and/or power
    293      * the relevant h/w blocks down.
    294      *
    295      * IMPORTANT NOTE: there is an implicit layer containing opaque black
    296      * pixels behind all the layers in the list.
    297      * It is the responsibility of the hwcomposer module to make
    298      * sure black pixels are output (or blended from).
    299      *
    300      * returns: 0 on success. An negative error code on error:
    301      *    HWC_EGL_ERROR: eglGetError() will provide the proper error code
    302      *    Another code for non EGL errors.
    303      *
    304      */
    305     int (*set)(struct hwc_composer_device *dev,
    306                 hwc_display_t dpy,
    307                 hwc_surface_t sur,
    308                 hwc_layer_list_t* list);
    309     /*
    310      * This hook is OPTIONAL.
    311      *
    312      * If non NULL it will be called by SurfaceFlinger on dumpsys
    313      */
    314     void (*dump)(struct hwc_composer_device* dev, char *buff, int buff_len);
    315 
    316     /*
    317      * This hook is OPTIONAL.
    318      *
    319      * (*registerProcs)() registers a set of callbacks the h/w composer HAL
    320      * can later use. It is FORBIDDEN to call any of the callbacks from
    321      * within registerProcs(). registerProcs() must save the hwc_procs_t pointer
    322      * which is needed when calling a registered callback.
    323      * Each call to registerProcs replaces the previous set of callbacks.
    324      * registerProcs is called with NULL to unregister all callbacks.
    325      *
    326      * Any of the callbacks can be NULL, in which case the corresponding
    327      * functionality is not supported.
    328      */
    329     void (*registerProcs)(struct hwc_composer_device* dev,
    330             hwc_procs_t const* procs);
    331 
    332     void* reserved_proc[6];
    333 
    334 } hwc_composer_device_t;
    335 
    336 
    337 /** convenience API for opening and closing a device */
    338 
    339 static inline int hwc_open(const struct hw_module_t* module,
    340         hwc_composer_device_t** device) {
    341     return module->methods->open(module,
    342             HWC_HARDWARE_COMPOSER, (struct hw_device_t**)device);
    343 }
    344 
    345 static inline int hwc_close(hwc_composer_device_t* device) {
    346     return device->common.close(&device->common);
    347 }
    348 
    349 
    350 /*****************************************************************************/
    351 
    352 __END_DECLS
    353 
    354 #endif /* ANDROID_INCLUDE_HARDWARE_HWCOMPOSER_H */
    355