winapigdidirect2ddxgi
Force Win32 common controls to draw on `ID2D1HwndRenderTarget`?
I draw most of my UI using ID2D1HwndRenderTarget, but I want some classic window controls: button, edit. How to
ID2D1HwndRenderTarget * canvas = nullptr; // it's global object
HWND button = nullptr; // it's global object
HWND edit = nullptr; // it's global object
HWND custom = nullptr; // it's global object
// mainWindow WinPproc
case WM_CREATE:
button = CreateWindowExW(0, L"button", L"Send", WS_CHILD | WS_VISIBLE, 10, 10, 120, 30, hWnd, BUTTON_ID, hInstance, 0); // win32 control
edit = CreateWindowExW(0, L"edit", L"Edit", WS_CHILD | WS_VISIBLE, 10, 50, 120, 30, hWnd, BUTTON_ID, hInstance, 0); // win32 control
custom = CreateWindowExW(0, L"custom", L"Custom", WS_CHILD | WS_VISIBLE, 10, 90, 120, 30, hWnd, BUTTON_ID, hInstance, 0); // it's my custom class
break;
case WM_PAINT:
BeginPaint(hWnd, nullptr);
render_target->BeginPaint();
... GUI rendering stuff ....
HRESULT result = render_target->EndDraw();
if(result != S_OK)
{
// Error handling
...
}
EndPaint(hWnd, nullptr);
break;
// custom WinProc
case WM_PAINT:
BeginPaint(hWnd, nullptr);
render_target->BeginPaint();
... rendering stuff ....
HRESULT result = render_target->EndDraw();
if(result != S_OK)
{
// Error handling
...
}
EndPaint(hWnd, nullptr);
break;
Only things painted with render_target are visible. I understand why: becausebutton and edit are default win32 controls, internally drawn using PAINTSTRUCT->HDC context. I read Direct2D and GDI Interoperability Overview and get the concept, but still don't know where this HDC intrecpet should take place? I don't want touch default control WM_PAINT. I have to supclass all default win32 controls?
How to force those Win32 controls to draw onto my render_target?
Solution
If you want to share a device context (HDC) between GDI and Direct2D, you can use a ID2D1DCRenderTarget and Bind to this HDC when you want to render on it.
This is demonstrated in this official sample : GDI/Direct2D Interoperability Sample
Note, as is, it doesn't compile/work with today's Visual Studio. So, here is a similar code here with a simple button and textbox:
#include <windows.h>
#include <stdlib.h>
#include <math.h>
#include <d2d1.h>
template<class Interface>
inline void
SafeRelease(Interface** ppInterfaceToRelease)
{
if (*ppInterfaceToRelease != NULL)
{
(*ppInterfaceToRelease)->Release();
(*ppInterfaceToRelease) = NULL;
}
}
EXTERN_C IMAGE_DOS_HEADER __ImageBase;
class DemoApp
{
public:
DemoApp();
~DemoApp();
HRESULT Initialize();
private:
HRESULT CreateDeviceIndependentResources();
HRESULT CreateDeviceResources();
void DiscardDeviceResources();
HRESULT OnRender(const PAINTSTRUCT& ps);
static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
private:
HWND m_hwnd;
ID2D1Factory* m_pD2DFactory;
ID2D1DCRenderTarget* m_pDCRT;
ID2D1SolidColorBrush* m_pBlackBrush;
};
int WINAPI WinMain(HINSTANCE /*hInstance*/, HINSTANCE /*hPrevInstance*/, LPSTR /*lpCmdLine*/, int /*nCmdShow*/)
{
if (SUCCEEDED(CoInitialize(NULL)))
{
DemoApp app;
if (SUCCEEDED(app.Initialize()))
{
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
CoUninitialize();
}
return 0;
}
DemoApp::DemoApp() :
m_hwnd(NULL),
m_pD2DFactory(NULL),
m_pDCRT(NULL),
m_pBlackBrush(NULL)
{
}
DemoApp::~DemoApp()
{
SafeRelease(&m_pD2DFactory);
SafeRelease(&m_pDCRT);
SafeRelease(&m_pBlackBrush);
}
HRESULT DemoApp::Initialize()
{
HRESULT hr;
hr = CreateDeviceIndependentResources();
if (SUCCEEDED(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 = (HINSTANCE)&__ImageBase;
wcex.hbrBackground = NULL;
wcex.lpszMenuName = NULL;
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.lpszClassName = L"D2DDemoApp";
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.
FLOAT dpiX, dpiY;
m_pD2DFactory->GetDesktopDpi(&dpiX, &dpiY);
m_hwnd = CreateWindow(
L"D2DDemoApp",
L"Direct2D Demo App",
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,
(HINSTANCE)&__ImageBase,
this
);
hr = m_hwnd ? S_OK : E_FAIL;
if (SUCCEEDED(hr))
{
ShowWindow(m_hwnd, SW_SHOWNORMAL);
UpdateWindow(m_hwnd);
}
}
return hr;
}
HRESULT DemoApp::CreateDeviceIndependentResources()
{
// Create D2D factory
return D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED, &m_pD2DFactory);
}
HRESULT DemoApp::CreateDeviceResources()
{
HRESULT hr = S_OK;
if (!m_pDCRT)
{
// Create a DC render target.
D2D1_RENDER_TARGET_PROPERTIES props = D2D1::RenderTargetProperties(
D2D1_RENDER_TARGET_TYPE_DEFAULT,
D2D1::PixelFormat(
DXGI_FORMAT_B8G8R8A8_UNORM,
D2D1_ALPHA_MODE_IGNORE),
0,
0,
D2D1_RENDER_TARGET_USAGE_NONE,
D2D1_FEATURE_LEVEL_DEFAULT
);
hr = m_pD2DFactory->CreateDCRenderTarget(&props, &m_pDCRT);
if (SUCCEEDED(hr))
{
// Create a black brush.
hr = m_pDCRT->CreateSolidColorBrush(D2D1::ColorF(D2D1::ColorF::Black), &m_pBlackBrush);
}
}
return hr;
}
void DemoApp::DiscardDeviceResources()
{
SafeRelease(&m_pDCRT);
SafeRelease(&m_pBlackBrush);
}
HRESULT DemoApp::OnRender(const PAINTSTRUCT& ps)
{
HRESULT hr;
RECT rc;
// Get the dimensions of the client drawing area.
GetClientRect(m_hwnd, &rc);
// Draw the pie chart with Direct2D.
// Create the DC render target.
hr = CreateDeviceResources();
if (SUCCEEDED(hr))
{
// Bind the DC to the DC render target.
hr = m_pDCRT->BindDC(ps.hdc, &rc);
m_pDCRT->BeginDraw();
m_pDCRT->SetTransform(D2D1::Matrix3x2F::Identity());
m_pDCRT->Clear(D2D1::ColorF(D2D1::ColorF::White));
m_pDCRT->DrawEllipse(D2D1::Ellipse(D2D1::Point2F(150.0f, 150.0f), 100.0f, 100.0f), m_pBlackBrush, 3.0);
m_pDCRT->DrawLine(
D2D1::Point2F(150.0f, 150.0f),
D2D1::Point2F((150.0f + 100.0f * 0.15425f), (150.0f - 100.0f * 0.988f)), m_pBlackBrush, 3.0
);
m_pDCRT->DrawLine(
D2D1::Point2F(150.0f, 150.0f),
D2D1::Point2F((150.0f + 100.0f * 0.525f), (150.0f + 100.0f * 0.8509f)), m_pBlackBrush, 3.0
);
m_pDCRT->DrawLine(
D2D1::Point2F(150.0f, 150.0f),
D2D1::Point2F((150.0f - 100.0f * 0.988f), (150.0f - 100.0f * 0.15425f)), m_pBlackBrush, 3.0
);
hr = m_pDCRT->EndDraw();
if (SUCCEEDED(hr))
{
// Draw the pie chart with GDI.
// Save the original object.
HGDIOBJ original = NULL;
original = SelectObject(ps.hdc, GetStockObject(DC_PEN));
HPEN blackPen = CreatePen(PS_SOLID, 3, 0);
SelectObject(ps.hdc, blackPen);
Ellipse(ps.hdc, 300, 50, 500, 250);
POINT pntArray1[2];
pntArray1[0].x = 400;
pntArray1[0].y = 150;
pntArray1[1].x = static_cast<LONG>(400 + 100 * 0.15425);
pntArray1[1].y = static_cast<LONG>(150 - 100 * 0.9885);
POINT pntArray2[2];
pntArray2[0].x = 400;
pntArray2[0].y = 150;
pntArray2[1].x = static_cast<LONG>(400 + 100 * 0.525);
pntArray2[1].y = static_cast<LONG>(150 + 100 * 0.8509);
POINT pntArray3[2];
pntArray3[0].x = 400;
pntArray3[0].y = 150;
pntArray3[1].x = static_cast<LONG>(400 - 100 * 0.988);
pntArray3[1].y = static_cast<LONG>(150 - 100 * 0.15425);
Polyline(ps.hdc, pntArray1, 2);
Polyline(ps.hdc, pntArray2, 2);
Polyline(ps.hdc, pntArray3, 2);
DeleteObject(blackPen);
// Restore the original object.
SelectObject(ps.hdc, original);
}
}
if (hr == D2DERR_RECREATE_TARGET)
{
hr = S_OK;
DiscardDeviceResources();
}
return hr;
}
LRESULT CALLBACK DemoApp::WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
if (message == WM_CREATE)
{
LPCREATESTRUCT pcs = (LPCREATESTRUCT)lParam;
SetWindowLongPtr(hwnd, GWLP_USERDATA, (LONG_PTR)pcs->lpCreateParams);
auto button = CreateWindowExW(0, L"button", L"Send", WS_CHILD | WS_VISIBLE, 10, 10, 120, 30, hwnd, (HMENU)1, (HINSTANCE)&__ImageBase, 0); // win32 control
auto edit = CreateWindowExW(0, L"edit", L"Edit", WS_CHILD | WS_VISIBLE, 10, 50, 120, 30, hwnd, (HMENU)2, (HINSTANCE)&__ImageBase, 0); // win32 control
return 1;
}
LRESULT result = 0;
DemoApp* pDemoApp = (DemoApp*)(GetWindowLongPtr(hwnd, GWLP_USERDATA));
bool wasHandled = false;
if (pDemoApp)
{
switch (message)
{
case WM_PAINT:
case WM_DISPLAYCHANGE:
{
PAINTSTRUCT ps;
BeginPaint(hwnd, &ps);
pDemoApp->OnRender(ps);
EndPaint(hwnd, &ps);
}
result = 0;
wasHandled = true;
break;
case WM_DESTROY:
{
PostQuitMessage(0);
}
result = 1;
wasHandled = true;
break;
}
}
if (!wasHandled)
{
result = DefWindowProc(hwnd, message, wParam, lParam);
}
return result;
}
And here is how it renders (left circle is Direct2D, right is aliased GDI):
