# Display - [简介](#section11660541593) - [目录](#section161941989596) - [接口说明](#section1551164914237) - [使用说明](#section129654513264) - [相关仓](#section1371113476307) ## 简介该仓下主要包含Display模块HDI（Hardware Driver Interface）接口定义及其实现，对上层图形服务提供显示驱动能力接口，HDI接口主要包括如下三大类： - DisplayLayer：负责显示图层的管理，包括图层创建、显示属性设置、图层填充及刷新等操作； - DisplayGralloc：负责显示模块内存的管理，包括内存的申请和释放、内存映射等操作； - DisplayGfx：提供硬件加速接口，包括硬件加速模块的初始化、位图搬移、规则图形的画线及填充等操作。 **图 1** DISPLAY模块HDI接口层框架图 ![](figures/hdi-architecture-of-the-display-module.png "hdi-architecture-of-the-display-module") ## 目录该仓下源代码目录结构如下所示 ``` /drivers/peripheral/display ├── hal # display模块的hal层代码 │ └── default # display模块hdi的默认实现 ├── interfaces # display模块对上层服务提供的驱动能力接口 │ └── include # display模块对外提供的接口定义 ├── test # display模块的测试代码 │ └── unittest # display模块的单元测试代码 ``` ### 接口说明 Display驱动提供给系统服务WMS可直接调用的驱动能力接口，按照功能分类三大类：显示图层子模块、显示内存子模块、硬件加速子模块，可以提供图层的创建和销毁、图层属性的设置，内存的申请和释放、映射和缓冲，矩形填充和位图搬移等能力。提供的部分接口说明如[表1 Display HDI接口列表](#table1513255710559)所示： **表 1** Display HDI接口列表

头文件	接口名称	功能描述
display_layer.h	int32_t (*InitDisplay)(uint32_t devId);	显示屏初始化
	int32_t (*DeinitDisplay)(uint32_t devId);	显示屏反初始化
	int32_t (GetDisplayInfo)(uint32_t devId, DisplayInfo dispInfo);	获取显示信息
	int32_t (OpenLayer)(uint32_t devId, const LayerInfo layerInfo, uint32_t *layerId);	创建layer图层
	int32_t (*CloseLayer)(uint32_t devId, uint32_t layerId);	销毁layer图层
	int32_t (*SetLayerVisible)(uint32_t devId, uint32_t layerId, bool visible);	设置layer是否可见
	int32_t (SetLayerDirtyRegion)(uint32_t devId, uint32_t layerId, IRect region);	设置layer刷新区域
	int32_t (Flush)(uint32_t devId, uint32_t layerId, LayerBuffer buffer);	刷新图层
	int32_t (GetLayerBuffer)(uint32_t devId, uint32_t layerId, LayerBuffer buffer);	获取图层buffer
display_gralloc.h	int32_t AllocMem(GrallocBuffer *buffer);	显示内存分配
	void FreeMem(GrallocBuffer *buffer);	显示内存释放
	void Mmap(GrallocBuffer buffer);	内存映射
	void MmapCache(GrallocBuffer buffer);	内存映射为cache
	int32_t Unmap(GrallocBuffer *buffer);	取消内存映射
	int32_t FlushCache(GrallocBuffer *buffer);	刷新cache里的内容到内存并且使cache里的内容无效
	int32_t FlushMCache(GrallocBuffer *buffer);	刷新Mmap映射的cache里的内容到内存并且使cache里的内容无效
display_gfx.h	int32_t InitGfx(void);	初始化硬件加速
	int32_t DeinitGfx(void);	反初始化硬件加速
	int32_t Blit(ISurface srcSurface, IRect srcRect, ISurface dstSurface, IRect dstRect);	位图搬移
	int32_t FillRect(ISurface surface, IRect rect, uint32_t color, GfxOpt *opt);	绘制矩形框

### 使用说明该仓核心功能是提供显示驱动能力接口供上层图形系统服务调用，提供的驱动能力接口统一归属为HDI接口层。通过如下简要示例代码说明Display HDI接口的使用： ``` #include "display_gfx.h" #include "display_gralloc.h" #include "display_layer.h" #include "display_type.h" #define DEVID 0 DisplayTest g_displayTest; static GrallocBuffer g_buffer; static int32_t GetDisplayInterfaces(void) { int32_t ret; ret = LayerInitialize(&g_displayTest.layerFuncs); if (ret != DISPLAY_SUCCESS || g_displayTest.layerFuncs == NULL) { HDF_LOGE("initialize layer failed"); return DISPLAY_FAILURE; } ret = GrallocInitialize(&g_displayTest.grallocFuncs); if (ret != DISPLAY_SUCCESS || g_displayTest.layerFuncs == NULL) { HDF_LOGE("initialize gralloc failed"); return DISPLAY_FAILURE; } ret = GfxInitialize(&g_displayTest.gfxFuncs); if (ret != DISPLAY_SUCCESS || g_displayTest.gfxFuncs == NULL) { HDF_LOGE("initialize gralloc failed"); return DISPLAY_FAILURE; } return DISPLAY_SUCCESS; } static int32_t DisplayUninit(void) { LayerUninitialize(g_displayTest.layerFuncs); GrallocUninitialize(g_displayTest.grallocFuncs); GfxUninitialize(g_displayTest.gfxFuncs); return DISPLAY_SUCCESS; } static void GetLayerInfo(LayerInfo *layInfo) { layInfo->width = g_displayTest.displayInfo.width; layInfo->height = g_displayTest.displayInfo.height; layInfo->bpp = LAYER_BPP; layInfo->pixFormat = PIXEL_FMT_RGBA_5551; layInfo->type = LAYER_TYPE_GRAPHIC; } static void WriteDataToBuf(int32_t width, int32_t height, uint16_t *pBuf) { int32_t x; int32_t y; for (y = ((height / LINE_WIDTH) - LINE_WIDTH); y < ((height / LINE_WIDTH) + LINE_WIDTH); y++) { for (x = 0; x < width; x++) { *((uint16_t*)pBuf + y * width + x) = HIFB_RED_1555; } } for (y = 0; y < height; y++) { for (x = ((width / LINE_WIDTH) - LINE_WIDTH); x < ((width / LINE_WIDTH) + LINE_WIDTH); x++) { *((uint16_t*)pBuf + y * width + x) = HIFB_RED_1555; } } } int DisplayServiceSample(void) { int32_t ret; g_displayTest.devId = DEVID; /* 获取display驱动接口 */ ret = GetDisplayInterfaces(); if (ret != DISPLAY_SUCCESS) { HDF_LOGE("get display interfaces ops failed"); return ret; } /* 初始化显示设备 */ if (g_displayTest.layerFuncs->InitDisplay != NULL) { ret = g_displayTest.layerFuncs->InitDisplay(g_displayTest.devId); if (ret != DISPLAY_SUCCESS) { HDF_LOGE("initialize display failed"); return DISPLAY_FAILURE; } } /* 获取显示设备的信息 */ if (g_displayTest.layerFuncs->GetDisplayInfo != NULL) { ret = g_displayTest.layerFuncs->GetDisplayInfo(g_displayTest.devId, &g_displayTest.displayInfo); if (ret != DISPLAY_SUCCESS) { HDF_LOGE("get disp info failed"); return DISPLAY_FAILURE; } } /* 打开显示设备的特定图层 */ if (g_displayTest.layerFuncs->OpenLayer != NULL) { LayerInfo layInfo; GetLayerInfo(&layInfo); ret = g_displayTest.layerFuncs->OpenLayer(g_displayTest.devId, &layInfo, &g_displayTest.layerId); if (ret != DISPLAY_SUCCESS) { HDF_LOGE("open layer failed"); return DISPLAY_FAILURE; } } /* 获取图层buffer并填充buffer */ if (g_displayTest.layerFuncs->GetLayerBuffer != NULL) { ret = g_displayTest.layerFuncs->GetLayerBuffer(g_displayTest.devId, g_displayTest.layerId, &g_displayTest.buffer); if (ret != DISPLAY_SUCCESS) { HDF_LOGE("get layer buffer failed"); return DISPLAY_FAILURE; } uint16_t *pBuf = (uint16_t *)g_displayTest.buffer.data.virAddr; WriteDataToBuf(g_displayTest.displayInfo.width, g_displayTest.displayInfo.height, pBuf); } /* 刷新图层数据进行显示 */ if (g_displayTest.layerFuncs->Flush != NULL) { ret = g_displayTest.layerFuncs->Flush(g_displayTest.devId, g_displayTest.layerId, &g_displayTest.buffer); if (ret != DISPLAY_SUCCESS) { HDF_LOGE("flush layer failed"); return DISPLAY_FAILURE; } } /* 关闭显示设备的特定图层 */ if (g_displayTest.layerFuncs->CloseLayer != NULL) { ret = g_displayTest.layerFuncs->CloseLayer(g_displayTest.devId, g_displayTest.layerId); if (ret != DISPLAY_SUCCESS) { HDF_LOGE("close layer failed"); return DISPLAY_FAILURE; } } /* 关闭显示设备 */ if (g_displayTest.layerFuncs->DeinitDisplay != NULL) { ret = g_displayTest.layerFuncs->DeinitDisplay(g_displayTest.devId); if (ret != DISPLAY_SUCCESS) { HDF_LOGE("deinit display failed"); return DISPLAY_FAILURE; } } /* 注销显示驱动接口 */ ret = DisplayUninit(); if (ret != DISPLAY_SUCCESS) { HDF_LOGE("DisplayUninit fail"); return ret; } return 0; } ``` ## 相关仓 [驱动子系统](https://gitee.com/openharmony/docs/blob/master/zh-cn/readme/%E9%A9%B1%E5%8A%A8%E5%AD%90%E7%B3%BB%E7%BB%9F.md) [drivers\_framework](https://gitee.com/openharmony/drivers_framework/blob/master/README_zh.md) [drivers\_adapter](https://gitee.com/openharmony/drivers_adapter/blob/master/README_zh.md) [drivers\_adapter\_khdf\_linux](https://gitee.com/openharmony/drivers_adapter_khdf_linux/blob/master/README_zh.md) [drivers\_peripheral](https://gitee.com/openharmony/drivers_peripheral)