How to build a simple visual tree
Note
For apps on Windows 10, we recommend using Windows.UI.Composition APIs instead of DirectComposition. For more info, see Modernize your desktop app using the Visual layer.
This topic demonstrates how to build a simple Microsoft DirectComposition visual tree. The example in this topic builds and composes a visual tree that consists of a root visual and three child visuals. The content of the root visual is a light-blue bitmap that serves as the background for the child visuals. This illustration shows the composition created by the example code in this topic.
What you need to know
Technologies
Prerequisites
Knowledge of:
- C/C++
- Microsoft Win32
- Component Object Model (COM)
Instructions
Step 1: Initialize the device and composition target objects
For more information, see How to initialize DirectComposition.
Step 2: Create the visual objects and set the bitmap content
Use the IDCompositionDevice::CreateVisual method to create the visuals, and the IDCompositionVisual::SetContent method to set the bitmap content of the visuals.
Note
In the following example, the first element of the m_hBitmaps array contains the bitmap for the root visual, and the remaining elements contain the bitmaps for the child visuals.
#define NUM_VISUALS 4 // number of visuals in the composition
HBITMAP m_hBitmaps[NUM_VISUALS];
HRESULT hr = S_OK;
IDCompositionVisual *pVisuals[NUM_VISUALS]{ };
IDCompositionSurface *pSurface{ nullptr };
// Create a visual objects and set their content.
for (int i = 0; i < NUM_VISUALS; i++)
{
hr = m_pDevice->CreateVisual(&pVisuals[i]);
if (SUCCEEDED(hr))
{
// This application-defined function creates a DirectComposition
// surface and renders a GDI bitmap onto the surface.
hr = MyCreateGDIRenderedDCompSurface(m_hBitmaps[i], &pSurface);
if (SUCCEEDED(hr))
{
// Set the bitmap content.
hr = pVisuals[i]->SetContent(pSurface);
}
SafeRelease(&pSurface);
}
if (FAILED(hr))
{
goto Cleanup;
}
}
The following application defined function shows how to create the Microsoft DirectComposition surface and render a Windows Graphics Device Interface (GDI) bitmap to the surface.
// MyCreateGDIRenderedDCompSurface - Creates a DirectComposition surface and
// copies the bitmap to the surface.
//
// Parameters:
// hBitmap - a GDI bitmap.
// ppSurface - the composition surface object.
//
HRESULT DemoApp::MyCreateGDIRenderedDCompSurface(HBITMAP hBitmap, IDCompositionSurface **ppSurface)
{
HRESULT hr = S_OK;
int bitmapWidth = 0;
int bitmapHeight = 0;
int bmpSize = 0;
BITMAP bmp = { };
HBITMAP hBitmapOld = NULL;
HDC hSurfaceDC = NULL;
HDC hBitmapDC = NULL;
IDXGISurface1 *pDXGISurface = nullptr;
POINT pointOffset = { };
hr = hBitmap ? S_OK : E_FAIL;
if (SUCCEEDED(hr))
{
// Get information about the bitmap.
bmpSize = GetObject(hBitmap, sizeof(BITMAP), &bmp);
}
hr = bmpSize ? S_OK : E_FAIL;
if (SUCCEEDED(hr))
{
// Save the bitmap dimensions.
bitmapWidth = bmp.bmWidth;
bitmapHeight = bmp.bmHeight;
// Create a DirectComposition-compatible surface that is the same size
// as the bitmap.
hr = m_pDevice->CreateSurface(bitmapWidth, bitmapHeight,
DXGI_FORMAT_B8G8R8A8_UNORM, DXGI_ALPHA_MODE_IGNORE, ppSurface);
}
hr = ppSurface ? S_OK : E_FAIL;
if (SUCCEEDED(hr))
{
hr = (*ppSurface)->BeginDraw(NULL, __uuidof(IDXGISurface1),
reinterpret_cast<void**>(&pDXGISurface), &pointOffset);
}
if (SUCCEEDED(hr))
{
pDXGISurface->GetDC(FALSE, &hSurfaceDC);
}
hr = hSurfaceDC ? S_OK : E_FAIL;
if (SUCCEEDED(hr))
{
hBitmapDC = CreateCompatibleDC(hSurfaceDC);
if (hBitmapDC != NULL)
{
hBitmapOld = (HBITMAP)SelectObject(hBitmapDC, hBitmap);
BitBlt(hSurfaceDC, pointOffset.x, pointOffset.y,
bitmapWidth, bitmapHeight, hBitmapDC, 0, 0, SRCCOPY);
if (hBitmapOld)
{
SelectObject(hBitmapDC, hBitmapOld);
}
DeleteDC(hBitmapDC);
}
pDXGISurface->ReleaseDC(NULL);
}
(*ppSurface)->EndDraw();
SafeRelease(&pDXGISurface);
return hr;
}
Step 3: Set the root visual
Set the horizontal and vertical offsets of the root visual, and then add it to the visual tree by calling the IDCompositionTarget::SetRoot method.
float xPosRoot = 50.0;
float yPosRoot = 50.0;
// Set the horizontal and vertical position of the root visual.
pVisuals[0]->SetOffsetX(xPosRoot);
pVisuals[0]->SetOffsetY(yPosRoot);
// Set the root visual of the visual tree.
hr = m_pCompTarget->SetRoot(pVisuals[0]);
Step 4: Add the child visuals, and commit the composition
Use methods exposed by each child visual's IDCompositionVisual interface to set the bitmap content and other properties, and then use the root visual's IDCompositionVisual::AddVisual method to add the child visuals to the root of the visual tree. Call IDCompositionDevice::Commit to commit the batch of commands to DirectComposition for processing. The resulting composition appears in the target window.
float xPosChild = 20.0f;
float yPosChild = 20.0f;
if (SUCCEEDED(hr))
{
// Set the positions of the child visuals and add them to the visual tree.
for (int i = 1; i < NUM_VISUALS; i++)
{
pVisuals[i]->SetOffsetX(xPosChild);
pVisuals[i]->SetOffsetY(
static_cast<float>((yPosChild * i) + (CHILD_BITMAP_HEIGHT * (i - 1))));
// Add the child visuals as children of the root visual.
pVisuals[0]->AddVisual(pVisuals[i], TRUE, nullptr);
}
}
// Commit the visual to be composed and displayed.
hr = m_pDevice->Commit();
Step 5: Free the DirectComposition objects
Free the visual objects as soon as you no longer need them. This next bit of code calls the application-defined SafeRelease macro to free the visual objects.
Cleanup:
// Free the visuals.
for (int i = 0; i < NUM_VISUALS; i++)
{
SafeRelease(&pVisuals[i]);
}
Also, remember to free the device and composition target objects before your application exits.
SafeRelease(&m_pD3D11Device);
SafeRelease(&m_pDevice);
SafeRelease(&m_pCompTarget);
Complete example
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
// PARTICULAR PURPOSE.
//
// Copyright (c) Microsoft Corporation. All rights reserved
#pragma once
// Modify the following definitions if you need to target a platform prior to the ones specified below.
#ifndef WINVER // Allow use of features specific to Windows 7 or later.
#define WINVER 0x0700 // Change this to the appropriate value to target other versions of Windows.
#endif
#ifndef _WIN32_WINNT // Allow use of features specific to Windows 7 or later.
#define _WIN32_WINNT 0x0700 // Change this to the appropriate value to target other versions of Windows.
#endif
#ifndef UNICODE
#define UNICODE
#endif
#define WIN32_LEAN_AND_MEAN // Exclude rarely-used items from Windows headers
// Windows Header Files:
#include <windows.h>
// C RunTime Header Files
#include <math.h>
#include <dcomp.h>
#include <d3d11.h>
/******************************************************************
* *
* Macros *
* *
******************************************************************/
template<class Interface>
inline void
SafeRelease(
Interface **ppInterfaceToRelease
)
{
if (*ppInterfaceToRelease != NULL)
{
(*ppInterfaceToRelease)->Release();
(*ppInterfaceToRelease) = NULL;
}
}
#ifndef Assert
#if defined( DEBUG ) || defined( _DEBUG )
#define Assert(b) if (!(b)) {OutputDebugStringA("Assert: " #b "\n");}
#else
#define Assert(b)
#endif //DEBUG || _DEBUG
#endif
#ifndef HINST_THISCOMPONENT
EXTERN_C IMAGE_DOS_HEADER __ImageBase;
#define HINST_THISCOMPONENT ((HINSTANCE)&__ImageBase)
#endif
// Application-defined constants
#define NUM_VISUALS 4 // number of visuals in the composition
#define CHILD_BITMAP_HEIGHT 96 // height, in pixels, of a child visual
#define NUM_BITMAPS 4 // number of bitmaps in the composition
/******************************************************************
* *
* DemoApp *
* *
******************************************************************/
class DemoApp
{
public:
DemoApp();
~DemoApp();
HRESULT Initialize();
void RunMessageLoop();
private:
HRESULT InitializeDirectCompositionDevice();
HRESULT CreateResources();
void DiscardResources();
HRESULT OnClientClick();
HRESULT DemoApp::LoadResourceGDIBitmap(
PCWSTR resourceName,
HBITMAP &hbmp
);
HRESULT DemoApp::MyCreateGDIRenderedDCompSurface(HBITMAP hBitmap, IDCompositionSurface **ppSurface);
static LRESULT CALLBACK WndProc(
HWND hWnd,
UINT message,
WPARAM wParam,
LPARAM lParam
);
private:
HWND m_hwnd;
HBITMAP m_hBitmaps[NUM_VISUALS];
ID3D11Device *m_pD3D11Device;
IDCompositionDevice *m_pDevice;
IDCompositionTarget *m_pCompTarget;
};
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
// PARTICULAR PURPOSE.
//
// Copyright (c) Microsoft Corporation. All rights reserved
// Instructions: Right-click in the client area to cause DirectCompostion
// to create a simple composition consisting a root visual and three child
// visuals. The root visual provides the background bitmap for the
// composition, and the three child visuals provide bitmaps that are
// composed on top of the root. All bitmaps are GDI.
#include "SimpleVisualTree.h"
/******************************************************************
* *
* The application entry point. *
* *
******************************************************************/
int WINAPI WinMain(
HINSTANCE /* hInstance */,
HINSTANCE /* hPrevInstance */,
LPSTR /* lpCmdLine */,
int /* nCmdShow */
)
{
// Ignore the return value because we want to run the program even in the
// unlikely event that HeapSetInformation fails.
HeapSetInformation(NULL, HeapEnableTerminationOnCorruption, NULL, 0);
if (SUCCEEDED(CoInitialize(NULL)))
{
{
DemoApp app;
if (SUCCEEDED(app.Initialize()))
{
app.RunMessageLoop();
}
}
CoUninitialize();
}
return 0;
}
/******************************************************************
* *
* DemoApp::DemoApp constructor *
* *
* Initialize member data. *
* *
******************************************************************/
DemoApp::DemoApp() :
m_hwnd(NULL),
m_hBitmaps(),
m_pD3D11Device(nullptr),
m_pDevice(nullptr),
m_pCompTarget(nullptr)
{
}
/******************************************************************
* *
* Release resources. *
* *
******************************************************************/
DemoApp::~DemoApp()
{
SafeRelease(&m_pD3D11Device);
SafeRelease(&m_pDevice);
SafeRelease(&m_pCompTarget);
}
/*******************************************************************
* *
* Create the application window. *
* *
*******************************************************************/
HRESULT DemoApp::Initialize()
{
HRESULT hr;
// Register the window class.
WNDCLASSEX wcex = { sizeof(WNDCLASSEX) };
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = DemoApp::WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = sizeof(LONG_PTR);
wcex.hInstance = HINST_THISCOMPONENT;
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);;
wcex.lpszMenuName = NULL;
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.lpszClassName = L"DirectCompDemoApp";
RegisterClassEx(&wcex);
// Create the application window.
//
// Because the CreateWindow function takes its size in pixels, we
// obtain the system DPI and use it to scale the window size.
int dpiX = 0;
int dpiY = 0;
HDC hdc = GetDC(NULL);
if (hdc)
{
dpiX = GetDeviceCaps(hdc, LOGPIXELSX);
dpiY = GetDeviceCaps(hdc, LOGPIXELSY);
ReleaseDC(NULL, hdc);
}
m_hwnd = CreateWindow(
L"DirectCompDemoApp",
L"DirectComposition Demo Application",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
static_cast<UINT>(ceil(640.f * dpiX / 96.f)),
static_cast<UINT>(ceil(480.f * dpiY / 96.f)),
NULL,
NULL,
HINST_THISCOMPONENT,
this
);
hr = m_hwnd ? S_OK : E_FAIL;
if (SUCCEEDED(hr))
{
ShowWindow(m_hwnd, SW_SHOWNORMAL);
UpdateWindow(m_hwnd);
// Initialize DirectComposition resources, such as the
// device object and composition target object.
hr = InitializeDirectCompositionDevice();
}
if (SUCCEEDED(hr))
{
hr = CreateResources();
}
return hr;
}
/******************************************************************
* *
* This method creates the DirectComposition device object and *
* and the composition target object. These objects endure for *
* the lifetime of the application. *
* *
******************************************************************/
HRESULT DemoApp::InitializeDirectCompositionDevice()
{
HRESULT hr = S_OK;
D3D_FEATURE_LEVEL featureLevelSupported;
IDXGIDevice *pDXGIDevice = nullptr;
// Create the D3D device object.
D3D11CreateDevice(
nullptr,
D3D_DRIVER_TYPE_HARDWARE,
NULL,
D3D11_CREATE_DEVICE_BGRA_SUPPORT,
NULL,
0,
D3D11_SDK_VERSION,
&m_pD3D11Device,
&featureLevelSupported,
NULL);
hr = (m_pD3D11Device == nullptr) ? E_UNEXPECTED : S_OK;
if (SUCCEEDED(hr))
{
// Create the DXGI device used to create bitmap surfaces.
hr = m_pD3D11Device->QueryInterface(&pDXGIDevice);
}
if (SUCCEEDED(hr))
{
// Create the DirectComposition device object.
hr = DCompositionCreateDevice(pDXGIDevice, __uuidof(IDCompositionDevice),
reinterpret_cast<void **>(&m_pDevice));
}
if (SUCCEEDED(hr))
{
// Create the composition target object.
hr = m_pDevice->CreateTargetForHwnd(m_hwnd, TRUE, &m_pCompTarget);
}
SafeRelease(&pDXGIDevice);
return hr;
}
/******************************************************************
* *
* This method creates the GDI bitmaps to be associated with *
* DirectComposition visual objects. *
* *
******************************************************************/
HRESULT DemoApp::CreateResources()
{
HRESULT hr = S_OK;
hr = LoadResourceGDIBitmap(L"Background", m_hBitmaps[0]);
hr = LoadResourceGDIBitmap(L"BlkKnight", m_hBitmaps[1]);
hr = LoadResourceGDIBitmap(L"BlkQueen", m_hBitmaps[2]);
hr = LoadResourceGDIBitmap(L"BlkRook", m_hBitmaps[3]);
return hr;
}
/******************************************************************
* *
* Discard device-specific resources. *
* *
******************************************************************/
void DemoApp::DiscardResources()
{
int i = 0;
while (i < NUM_VISUALS)
{
DeleteObject(m_hBitmaps[i++]);
}
}
/******************************************************************
* *
* The main window's message loop. *
* *
******************************************************************/
void DemoApp::RunMessageLoop()
{
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
/******************************************************************
* *
* Called whenever the user clicks the client area of the main *
* window. This method builds a simple visual tree consisting of *
* a root visual and three child visuals. *
******************************************************************/
HRESULT DemoApp::OnClientClick()
{
HRESULT hr = S_OK;
IDCompositionVisual *pVisuals[NUM_VISUALS] = { };
IDCompositionSurface *pSurface = nullptr;
// Create a visual objects and set their content.
for (int i = 0; i < NUM_VISUALS; i++)
{
hr = m_pDevice->CreateVisual(&pVisuals[i]);
if (SUCCEEDED(hr))
{
// This application-defined function creates a DirectComposition
// surface and renders a GDI bitmap onto the surface.
hr = MyCreateGDIRenderedDCompSurface(m_hBitmaps[i], &pSurface);
if (SUCCEEDED(hr))
{
// Set the bitmap content.
hr = pVisuals[i]->SetContent(pSurface);
}
SafeRelease(&pSurface);
}
if (FAILED(hr))
{
goto Cleanup;
}
}
float xPosRoot = 50.0;
float yPosRoot = 50.0;
// Set the horizontal and vertical position of the root visual.
pVisuals[0]->SetOffsetX(xPosRoot);
pVisuals[0]->SetOffsetY(yPosRoot);
// Set the root visual of the visual tree.
hr = m_pCompTarget->SetRoot(pVisuals[0]);
float xPosChild = 20.0f;
float yPosChild = 20.0f;
if (SUCCEEDED(hr))
{
// Set the positions of the child visuals and add them to the visual tree.
for (int i = 1; i < NUM_VISUALS; i++)
{
pVisuals[i]->SetOffsetX(xPosChild);
pVisuals[i]->SetOffsetY(
static_cast<float>((yPosChild * i) + (CHILD_BITMAP_HEIGHT * (i - 1))));
// Add the child visuals as children of the root visual.
pVisuals[0]->AddVisual(pVisuals[i], TRUE, nullptr);
}
}
// Commit the visual to be composed and displayed.
hr = m_pDevice->Commit();
Cleanup:
// Free the visuals.
for (int i = 0; i < NUM_VISUALS; i++)
{
SafeRelease(&pVisuals[i]);
}
return hr;
}
/******************************************************************
* *
* The window's message handler. *
* *
******************************************************************/
LRESULT CALLBACK DemoApp::WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
LRESULT result = 0;
if (message == WM_CREATE)
{
LPCREATESTRUCT pcs = (LPCREATESTRUCT)lParam;
DemoApp *pDemoApp = (DemoApp *)pcs->lpCreateParams;
::SetWindowLongPtrW(
hwnd,
GWLP_USERDATA,
PtrToUlong(pDemoApp)
);
result = 1;
}
else
{
DemoApp *pDemoApp = reinterpret_cast<DemoApp *>(static_cast<LONG_PTR>(
::GetWindowLongPtrW(
hwnd,
GWLP_USERDATA
)));
bool wasHandled = false;
if (pDemoApp)
{
switch (message)
{
case WM_LBUTTONDOWN:
{
pDemoApp->OnClientClick();
}
case WM_DISPLAYCHANGE:
{
InvalidateRect(hwnd, NULL, FALSE);
}
wasHandled = true;
result = 0;
break;
case WM_DESTROY:
{
PostQuitMessage(0);
pDemoApp->DiscardResources();
}
wasHandled = true;
result = 1;
break;
}
}
if (!wasHandled)
{
result = DefWindowProc(hwnd, message, wParam, lParam);
}
}
return result;
}
/******************************************************************
* *
* This method loads the specified GDI bitmap from the *
* application resources, creates a new bitmap that is in a *
* format that DirectComposition can use, and copies the contents *
* of the original bitmap to the new bitmap. *
* *
******************************************************************/
HRESULT DemoApp::LoadResourceGDIBitmap(PCWSTR resourceName, HBITMAP &hbmp)
{
// Load the bitmap from the application resources.
hbmp = static_cast<HBITMAP>(LoadImageW(HINST_THISCOMPONENT, resourceName,
IMAGE_BITMAP, 0, 0, LR_DEFAULTCOLOR));
return hbmp ? S_OK : E_FAIL;
}
// MyCreateGDIRenderedDCompSurface - Creates a DirectComposition surface and
// copies the bitmap to the surface.
//
// Parameters:
// hBitmap - a GDI bitmap.
// ppSurface - the composition surface object.
//
HRESULT DemoApp::MyCreateGDIRenderedDCompSurface(HBITMAP hBitmap, IDCompositionSurface **ppSurface)
{
HRESULT hr = S_OK;
int bitmapWidth = 0;
int bitmapHeight = 0;
int bmpSize = 0;
BITMAP bmp = { };
HBITMAP hBitmapOld = NULL;
HDC hSurfaceDC = NULL;
HDC hBitmapDC = NULL;
IDXGISurface1 *pDXGISurface = nullptr;
POINT pointOffset = { };
hr = hBitmap ? S_OK : E_FAIL;
if (SUCCEEDED(hr))
{
// Get information about the bitmap.
bmpSize = GetObject(hBitmap, sizeof(BITMAP), &bmp);
}
hr = bmpSize ? S_OK : E_FAIL;
if (SUCCEEDED(hr))
{
// Save the bitmap dimensions.
bitmapWidth = bmp.bmWidth;
bitmapHeight = bmp.bmHeight;
// Create a DirectComposition-compatible surface that is the same size
// as the bitmap.
hr = m_pDevice->CreateSurface(bitmapWidth, bitmapHeight,
DXGI_FORMAT_B8G8R8A8_UNORM, DXGI_ALPHA_MODE_IGNORE, ppSurface);
}
hr = ppSurface ? S_OK : E_FAIL;
if (SUCCEEDED(hr))
{
hr = (*ppSurface)->BeginDraw(NULL, __uuidof(IDXGISurface1),
reinterpret_cast<void**>(&pDXGISurface), &pointOffset);
}
if (SUCCEEDED(hr))
{
pDXGISurface->GetDC(FALSE, &hSurfaceDC);
}
hr = hSurfaceDC ? S_OK : E_FAIL;
if (SUCCEEDED(hr))
{
hBitmapDC = CreateCompatibleDC(hSurfaceDC);
if (hBitmapDC != NULL)
{
hBitmapOld = (HBITMAP)SelectObject(hBitmapDC, hBitmap);
BitBlt(hSurfaceDC, pointOffset.x, pointOffset.y,
bitmapWidth, bitmapHeight, hBitmapDC, 0, 0, SRCCOPY);
if (hBitmapOld)
{
SelectObject(hBitmapDC, hBitmapOld);
}
DeleteDC(hBitmapDC);
}
pDXGISurface->ReleaseDC(NULL);
}
(*ppSurface)->EndDraw();
SafeRelease(&pDXGISurface);
return hr;
}