支持缩放的浏览器解决方法

支持缩放的浏览器
我用StretchBlt函数做了一个DC缩放的函数，现在还没有限定缩放极限就是试了一下速度，代码如下。

void PictureZoom(HDC hdc, float fZoomRatio)
{
if (fZoomRatio == 1)
return ;

static float fCurRatio = 0;
HDC BufferDC = CreateCompatibleDC(hdc);
HBITMAP BufferDCBmp = CreateCompatibleBitmap(hdc, g_dwScreenWidth, g_dwScreenHeight);

SelectObject(BufferDC, BufferDCBmp);

if (!g_hSrcPicDC) //当一张新图片进行缩放时
{
RECT rc;
HDC tempDC = CreateCompatibleDC(hdc);
HBITMAP tempDCBmp = SHLoadImageFile(g_cDlist.m_pCurNode->szFilePath);
SelectObject(tempDC, tempDCBmp);

g_hSrcPicDC = CreateCompatibleDC(hdc);
g_hSrcPicDCBmp = CreateCompatibleBitmap(hdc, g_dwScreenWidth, g_dwScreenHeight);
SelectObject(g_hSrcPicDC, g_hSrcPicDCBmp);

BitBltByScale(g_hSrcPicDC, g_dwScreenWidth, g_dwScreenHeight, tempDC, g_cDlist.m_pCurNode->Width, g_cDlist.m_pCurNode->Height, &rc);

//初始化当前显示区域
g_drawRc.left = 0;
g_drawRc.top = 0;
g_drawRc.right = g_dwScreenWidth;
g_drawRc.bottom = g_dwScreenHeight;

if (tempDC)
DeleteDC(tempDC);
if (tempDCBmp)
DeleteObject(tempDCBmp);
}

//计算缩放后的显示区域， 放大时显示区域是缩小，缩小时显示区域是放大
RECT tempRc = {g_drawRc.left, g_drawRc.top, g_drawRc.right, g_drawRc.bottom};

tempRc.right = tempRc.right / fZoomRatio;
tempRc.bottom = tempRc.bottom / fZoomRatio;
tempRc.left = g_dwScreenWidth / 2 - tempRc.right / 2;
tempRc.top = g_dwScreenHeight / 2 - tempRc.bottom / 2;

CopyRect(&g_drawRc, &tempRc);

StretchBlt(BufferDC, 0, 0, g_dwScreenWidth, g_dwScreenHeight, 
g_hSrcPicDC, g_drawRc.left, g_drawRc.top, g_drawRc.right, g_drawRc.bottom, SRCCOPY);
if (g_dwFlags & STATE_MENU_BTN)
DrawMenuBtn(BufferDC);
BitBlt(hdc, 0, 0, g_dwScreenWidth, g_dwScreenHeight, BufferDC, 0, 0, SRCCOPY);

g_dwFlags |= STATE_ZOOM;

CLEAN:

if (BufferDC)
DeleteDC(BufferDC);
if (BufferDCBmp)
DeleteObject(BufferDCBmp);
}

速度不是很流畅，请问有其它比较快速 流畅的方式吗
（WIN32）





------解决方案--------------------
要使用快的算法，你的自己写缩放算法，而不是使用API,并且的使用ASM优化