请问各位C博客大神MFC如何实现对 PNG图片的旋转

[zhaoyijie888]

最近工作遇到要对PNG图片实现旋转的功能，在线搜了很多发现都不能满足要求，有没大神可以指点一下，感激不尽啊


，最终实现效果是输入角度指针能在刻度盘上旋转对应的角度，有知道怎么旋转的大神求告知一下，感激不尽

[念苍生_君莫笑]

这种东西我觉得还是预先把各个角度的模板图存好靠谱，图像变换得来的效果可能会有视觉上的影响

[BeanJoy]

图像旋转算法与实现

[阿源是少年]

用GDI+可以很容易实现http://blog.csdn.net/xiaohuh421/article/details/40979477

[schlafenhamster]

	CPaintDC dc(this); // device context for painting

	Image image(L"Indicator.png");
	int w,h;
	w=image.GetWidth();
	h=image.GetHeight();

	CRect rect;
	rect.SetRect(0,0,w,h);
//
	CDC memDC;
    memDC.CreateCompatibleDC(&dc);
	HBITMAP hbmp=CreateCompatibleBitmap(dc.m_hDC,w,h);
	memDC.SelectObject(hbmp);
// memDC
    Graphics graphics(memDC.m_hDC);
// argb
	SolidBrush brush(Color(128,128,255,255));
	graphics.FillRectangle(&brush,0,0,w,h);//
//
	graphics.TranslateTransform((REAL)(w/2),(REAL)(h/2));
	graphics.RotateTransform(45.0);
	graphics.TranslateTransform((REAL)(-w/2),(REAL)(-h/2));
	graphics.DrawImage(&image,0,0,w,h);
	HDC hdc = graphics.GetHDC();
	::BitBlt(dc.m_hDC,0,0,w,h,hdc,0,0,SRCCOPY);
	graphics.ReleaseHDC(hdc);

CPaintDC dc(this); // device context for painting

Image image(L"Indicator.png");
int w,h;
w=image.GetWidth();
h=image.GetHeight();

CRect rect;
rect.SetRect(0,0,w,h);
//
CDC memDC;
memDC.CreateCompatibleDC(&dc);
HBITMAP hbmp=CreateCompatibleBitmap(dc.m_hDC,w,h);
memDC.SelectObject(hbmp);
// memDC
Graphics graphics(memDC.m_hDC);
// argb
SolidBrush brush(Color(128,128,255,255));
graphics.FillRectangle(&brush,0,0,w,h);//
//
graphics.TranslateTransform((REAL)(w/2),(REAL)(h/2));
graphics.RotateTransform(45.0);
graphics.TranslateTransform((REAL)(-w/2),(REAL)(-h/2));
graphics.DrawImage(&image,0,0,w,h);
HDC hdc = graphics.GetHDC();
::BitBlt(dc.m_hDC,0,0,w,h,hdc,0,0,SRCCOPY);
graphics.ReleaseHDC(hdc);[/code]
[/code]

[shiter]

顶楼上，真厉害，那啥，四个通道呢，估计得注意一下这点

[zhaoyijie888]

楼上大神，两个图合起来怎么整啊？我还是弄不好啊

[schlafenhamster]

	CPaintDC dc(this); // device context for painting
// 指针
	Image image(L"Indicator.png");
	int w,h;
	w=image.GetWidth();
	h=image.GetHeight();
// 背景
	CRect rect;
	rect.SetRect(0,0,w,h);
// on memDC
	CDC memDC;
    memDC.CreateCompatibleDC(&dc);
	HBITMAP hbmp=CreateCompatibleBitmap(dc.m_hDC,w,h);
	memDC.SelectObject(hbmp);
    Graphics graphics(memDC.m_hDC);
// argb 背景与对话框同色
	SolidBrush brush1(Color(255,210,210,210));
	graphics.FillRectangle(&brush1, 0, 0, w, h);  
// background 画面板
	Image imageBk(L"Pannel.png");
	TextureBrush brush(&imageBk); 
	graphics.FillRectangle(&brush,0,0,w,h);//
// moveto center
	graphics.TranslateTransform((REAL)(w/2),(REAL)(h/2));
// ratate 90 degree
	graphics.RotateTransform(131.0);// 原图有 offset = 42.0 degree
// move back
	graphics.TranslateTransform((REAL)(-w/2),(REAL)(-h/2));
// draw indicator 指针
	graphics.DrawImage(&image,0,0,w,h);
// draw to screen
	HDC hdc = graphics.GetHDC();
	::BitBlt(dc.m_hDC,0,0,w,h,hdc,0,0,SRCCOPY);
	graphics.ReleaseHDC(hdc);