D2D1在高DPI下有明显的锯齿

Question

写一个简单的demo来验证问题，DPI越高，别名越明显，文字是一样的，尝试使用SetAntialiasMode和SetTextAntialiasMode没有改善，我的系统是win10专业版。

有没有办法在高DPI下实现抗锯齿？

static ID2D1Factory * g_factory;
static IDWriteFactory*  g_dwrite_factory;
static ID2D1HwndRenderTarget * g_render_target;
static INT32 _dpi_x = 96;
static INT32 _dpi_y = 96;

#define DIP_TEST

void OnSize(LPARAM lparam)
{    
UINT32 width = LOWORD(lparam);
UINT32 height = HIWORD(lparam);

UINT32 pixel_width = (UINT32)(width * _dpi_x / 96.0f);
UINT32 pixel_height = (UINT32)(height * _dpi_x / 96.0f);

if (g_render_target)
g_render_target->Resize(D2D1::SizeU(pixel_width, pixel_height));
}

bool AppInit()
{
#ifdef DIP_TEST
SetProcessDPIAware();
_dpi_x = 384;
_dpi_y = 384; 
#endif

D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED, &g_factory);
DWriteCreateFactory(DWRITE_FACTORY_TYPE_SHARED, __uuidof(IDWriteFactory), reinterpret_cast<IUnknown**>(&g_dwrite_factory));

RECT rc;
GetClientRect(g_hwnd, &rc);

UINT32 logic_width = rc.right - rc.left;
UINT32 logic_height = rc.bottom - rc.top;
UINT32 w = (UINT32)(logic_width * _dpi_x / 96.0f);
UINT32 h = (UINT32)(logic_height * _dpi_x / 96.0f);

D2D1_PIXEL_FORMAT pixelFormat = D2D1::PixelFormat(DXGI_FORMAT_B8G8R8A8_UNORM, D2D1_ALPHA_MODE_PREMULTIPLIED);
D2D1_RENDER_TARGET_PROPERTIES props = D2D1::RenderTargetProperties(D2D1_RENDER_TARGET_TYPE_DEFAULT, pixelFormat);//D2D1_RENDER_TARGET_TYPE_SOFTWARE为了截图
#ifdef DIP_TEST
props.dpiX = (float)_dpi_x;
props.dpiY = (float)_dpi_y;
#endif

g_factory->CreateHwndRenderTarget(props,
D2D1::HwndRenderTargetProperties(g_hwnd, D2D1::SizeU(w, h)),
&g_render_target);

return true;
}

void OnPaint()
{
if (!g_render_target)
    return;

...
g_render_target->BeginDraw();
g_render_target->Clear(D2D1::ColorF(0.f, 0.f, 0.0f));
//g_render_target->SetAntialiasMode(D2D1_ANTIALIAS_MODE_PER_PRIMITIVE);
stroke_brush->SetColor(D2D1::ColorF(1.0f, 0.0f, 0.0f, 1.0f));
D2D1_RECT_F textLayoutRect = D2D1::RectF(100.0f, 150.0f, 600.0f, 600.0f);
g_render_target->DrawTextW(sz, text_len, dwrite_text_format, textLayoutRect, stroke_brush, D2D1_DRAW_TEXT_OPTIONS_NONE, DWRITE_MEASURING_MODE_NATURAL);     
g_render_target->DrawEllipse(D2D1::Ellipse(D2D1::Point2F(300.5, 200.5), 250, 150), stroke_brush, 2);
g_render_target->EndDraw(); 
...
}

Answer 1

您似乎在创建 window 后启用了 DPI 感知。您应该改为在应用程序清单中声明 dpi 感知。也不需要像 (logic_width * _dpi_x / 96.0f); 那样执行手动尺寸缩放，因为 window 大小已经是物理像素，而不是 logical_pixels。

D2D1在高DPI下有明显的锯齿

D2D1 has obvious aliasing under high DPI

direct2d

hdpi