我尝试在地图应用程序中使用Direct2D。但它比GDI慢得多,因为D2D绘制整个屏幕。 当用户滚动窗口时,GDI滚动视频缓冲区并仅绘制一小部分屏幕。这就是GDI比D2D更快的原因。
我的问题是:
ScrollWindow()
)InvalidateRect()
和GetClipBox()
)我找到了一个解决方案 How to scroll window contents using Direct2D api? 有没有人有更好的解决方案?
我的例子是:
D2D1::Matrix3x2F matrix;
CPoint org(GetDeviceScrollPosition());
FLOAT scaleW=(FLOAT)m_totalLog.cx/m_totalDev.cx;
FLOAT scaleH=(FLOAT)m_totalLog.cy/m_totalDev.cy;
if(scaleW > scaleH) scaleW = scaleH;
matrix.SetProduct(D2D1::Matrix3x2F::Scale(scaleW, scaleH, D2D1::Point2F(0.0f, 0.0f)), D2D1::Matrix3x2F::Translation((FLOAT)-org.x, (FLOAT)-org.y));
//"Scale Device Screen" * "Scroll Device Screen"
pRenderTarget->SetTransform(matrix);
CScrollView
中的。但表现很差。
答案 0 :(得分:0)
我找到了一个解决方案:使用“CDCRenderTarget”。然后我们可以在CScrollView中使用scroll / GetClipBox()函数。
void CMFCGdi_D2D2View::OnDraw(CDC* pDC)
{
CMFCGdi_D2D2Doc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
if (!pDoc) return;
// TODO: add draw code for native data here
#define LINE_WIDTH 3
CRect rcInvalid;
pDC->GetClipBox(rcInvalid);
if(rcInvalid.left==0 && rcInvalid.top==0) pDC->FillSolidRect(rcInvalid, RGB(255,0,0));
else pDC->FillSolidRect(rcInvalid, RGB(0, 255, 0)); //visible redraw area
CRect rcLogical;
GetClientRect(rcLogical);
rcLogical.bottom+=GetScrollPosition().y;
rcLogical.right+=GetScrollPosition().x;
m_RenderTarget.BindDC(*pDC, rcLogical);
m_RenderTarget.BeginDraw();
m_RenderTarget.SetTransform(D2D1::Matrix3x2F::Identity());
m_RenderTarget.DrawEllipse(CD2DEllipse(CD2DPointF(150.0f, 150.0f), CD2DSizeF(100., 100.)), m_pBlackBrush, LINE_WIDTH);
m_RenderTarget.DrawLine(CD2DPointF(150.0f, 150.0f), CD2DPointF(150.0f + 100.0f * 0.15425f, 150.0f - 100.0f * 0.988f),
m_pBlackBrush, LINE_WIDTH);
m_RenderTarget.DrawLine(CD2DPointF(150.0f, 150.0f), CD2DPointF(150.0f + 100.0f * 0.525f, 150.0f + 100.0f * 0.8509f),
m_pBlackBrush, LINE_WIDTH);
m_RenderTarget.DrawLine(CD2DPointF(150.0f, 150.0f), CD2DPointF(150.0f - 100.0f * 0.988f, 150.0f - 100.0f * 0.15425f),
m_pBlackBrush, LINE_WIDTH);
HRESULT hr = m_RenderTarget.EndDraw();
if (SUCCEEDED(hr))
{
// Draw the pie chart with GDI.
CPen penBlack(PS_SOLID, LINE_WIDTH, RGB(255, 0, 0));
CPen* pOldPen = pDC->SelectObject(&penBlack);
pDC->Ellipse(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);
pDC->Polyline(pntArray1, 2);
pDC->Polyline(pntArray2, 2);
pDC->Polyline(pntArray3, 2);
pDC->SelectObject(&pOldPen);
}
}