如何对图片进行放大或缩小

[xf_pan]

我有一个函数,功能是显示程序里用到的画图,现在需要加一个放大或是缩小功能,没做过这方面的,没思路了,有谁做个吗,大家讨论下吧,

_VOID Canvas_Flip(_HANDLE hCanvas, _INT nX, _INT nY, _INT nWidth, _INT nHeight)
{
	HDC	hDC = (HDC)::SendMessage(SimulatorData.m_hMainFrame, UM_GetDrawDevices, NULL, NULL);
	_CANVASOBJECT*	pCanvas = (_CANVASOBJECT*)hCanvas;
	if (hDC && pCanvas)
	{
		_RECT	rect;
		GetScreenRect(&rect);
		
		if ((MediaPlayerRect.nWidth <= 0) || (MediaPlayerRect.nHeight <= 0))
			BitBlt(hDC, rect.nLeft + nX, rect.nTop + nY, nWidth, nHeight, pCanvas->hMemDC, nX, nY, SRCCOPY);
		else
		{

			_INT	x1 = nX, x2 = MediaPlayerRect.nLeft, x3 = MediaPlayerRect.nLeft + MediaPlayerRect.nWidth, x4 = nX + nWidth;
			_INT	y1 = nY, y2 = MediaPlayerRect.nTop, y3 = MediaPlayerRect.nTop + MediaPlayerRect.nHeight, y4 = nY + nHeight;
			if (x4 > x1 > 0 && y2 > y1)
				BitBlt(hDC, rect.nLeft + x1, rect.nTop + y1, x4 - x1, y2 - y1, pCanvas->hMemDC, x1, y1, SRCCOPY);
			if (x2 > x1 > 0 && y3 > y2)
				BitBlt(hDC, rect.nLeft + x1, rect.nTop + y2, x2 - x1, y3 - y2, pCanvas->hMemDC, x1, y2, SRCCOPY);
			if (x4 > x3 > 0 && y3 > y2)
				BitBlt(hDC, rect.nLeft + x3, rect.nTop + y2, x4 - x3, y3 - y2, pCanvas->hMemDC, x3, y2, SRCCOPY);
			if (x4 > x1 > 0 && y4 > y3)
				BitBlt(hDC, rect.nLeft + x1, rect.nTop + y3, x4 - x1, y4 - y3, pCanvas->hMemDC, x1, y3, SRCCOPY);
					}

	}
	::SendMessage(SimulatorData.m_hMainFrame, UM_ReleaseDrawDevices, (WPARAM)hDC, NULL);
}

[aaaa3105563]

UP

[ltc_mouse]

StretchBlt/SetStretchBltMode 就能实现缩放吧

[光宇广贞]

http://www.host01.com/article/software/cc/20060917184438949.htm

使用GDI+缩放图片

[猫已经找不回了]

http://topic.csdn.net/t/20050413/09/3931691.html

有代码，你看吧

[mxhbj]

http://topic.csdn.net/t/20050413/09/3931691.html

[xf_pan]

非常感谢大家,,问题解决了。。

[Sou2012]

学习了！