UWP Development Detail records: Loading image files to d2d bitmaps and D3D textures

Loading a file in the UWP typically creates the StorageFile object first, and then calls the Storagefile.openreadasync method to get a Irandomaccessstream interface to read the data:

1 await Storagefile.getfilefromapplicationuriasync (Thenew Uri ("ms-appx:///assets/sample.jpg  ", Urikind.absolute)); 2 await image_file. OpenReadAsync ();

Starting with a Irandomaccessstream stream, the steps to load the image (C + +/CX implementation):

1. Convert irandomaccessstream^ to Isream interface:

1 comptr<istream> source_stream; 2 dx::throwiffailed (:: Createstreamoverrandomaccessstream (Stream, Iid_ppv_args (&source_stream)));

2. Call the Iwicimagingfactory::createdecoderfromstream method (assuming the Iwicimagingfactory object is created) to create a IWICBitmapDecoder object for image decoding, and eventually get The Iwicformatconverter object is converted to a bitmap format suitable for D2D/D3D:

Comptr<iwicbitmapdecoder>decoder;dx::throwiffailed (_device_resources->getwicimagingfactory ()->createdecoderfromstream (Source_stream. Get (), nullptr, Wicdecodemetadatacacheondemand, &decoder)); ComPtr<IWICBitmapFrameDecode>frame;dx::throwiffailed (Decoder->getframe (0, &frame));//Convert the image to a pixel format supported by DIRECT2D. 32bppPBGRA are guaranteed to being supported on all hardware.< /c3>Comptr<iwicformatconverter>covert;dx::throwiffailed (_device_resources->getwicimagingfactory ()->createformatconverter (&covert));D X::throwiffailed (Covert->initialize (frame. Get (), Guid_wicpixelformat32bpppbgra, Wicbitmapdithertypenone, nullptr,0.0f, Wicbitmappalettetypecustom));

3. If the image is for d2d, you can now create the D2D bitmap directly with the Id2d1devicecontext::createbitmapfromwicbitmap method:

Comptr<id2d1bitmap1> d2d_bitmap;dx::throwiffailed (_device_resources->getd2ddevicecontext ()- >createbitmapfromwicbitmap (Covert. Get (), &d2d_bitmap));

4. If you want to use D3D, you need to create the D3D texture first:

//creating D3D Textures for 3D renderingD3d11_texture2d_desc Tex_desc = {0};tex_desc. ArraySize=1; Tex_desc. Bindflags= D3d11_bind_render_target |D3d11_bind_shader_resource;tex_desc. Cpuaccessflags=0; Tex_desc. Format=Dxgi_format_b8g8r8a8_unorm;tex_desc. Height=Height;tex_desc. Width=Width;tex_desc. Miplevels=1; Tex_desc. Miscflags=0; Tex_desc. Sampledesc.count=1; Tex_desc. Sampledesc.quality=0; Tex_desc. Usage=D3d11_usage_default; ComPtr<ID3D11Texture2D>image_texture;dx::throwiffailed (_device_resources->getd3ddevice ()->createtexture2d (&tex_desc, NULL, &image_texture));

5. Get the Idxgisurface interface from the Id3d11texture2d object, D2D and D3D can only interact with DXGI:

Comptr<idxgisurface> dxgi_surface;dx::throwiffailed (image_texture. As (&dxgi_surface));

6. Create the D2D render target with the Id2d1factory::createdxgisurfacerendertarget method:

 float  Dpix = 1.0f  ; float  Dpiy = 1.0f  ;_device_resources ->getd2dfactory ()->getdesktopdpi (&dpix, &< Span style= "color: #000000;"            >DPIY);D 2d1_render_target_properties props  = D2d1::rendertargetproperties (             D2d1_render_target_type_default, D2d1::P ixelformat (Dxgi_format_b8g8r8a8_unorm, d2d1_alpha_mode_premultiplied), Dpix, DPIY); COMPTR  <id2d1rendertarget> render_target;dx::throwiffailed (_device_ Resources ->getd2dfactory ()->createdxgisurfacerendertarget (dxgi_surface. Get (), props, &render_target)); 

7. Create a bitmap using the Id2d1rendertarget::createbitmapfromwicbitmap method (note that you cannot use the bitmap created in step 3rd directly, it is a different render target and the device-dependent bitmap is not generic):

Comptr<id2d1bitmap> bitmap;dx::throwiffailed (render_target->createbitmapfromwicbitmap (Covert. Get (), &bitmap));

8. Draw the bitmap to the render target, which is actually drawn to the D3D texture:

Render_target->BeginDraw (); Render_target-drawbitmap (bitmap. Get ()); Render_target->enddraw ();

Reference: MSDN Overview of DIRECT2D and Direct3D interoperability

UWP Development Detail records: Loading image files to d2d bitmaps and D3D textures