VFP下更改图像分辨率

VFP下,利用API函数GdipLoadImageFromFile打开图片,GdipBitmapSetResolution更改图像分辨率,GdipSaveImageToFile进行保存新文件。

VFP下更改图像分辨率(DPI)

编程方法：新建立一个位图，接着把新建立的位图设置成需要的分辨率，然后把需要修改的图片写到新文图上，最后保存。

DECLARE Long GdipBitmapSetResolution IN GDIPLUS.DLL Long nBitmap, Single xdpi, Single ydpi DECLARE INTEGER GdipLoadImageFromFile IN gdiplus.DLL STRING wFilename, INTEGER @nImage DECLARE INTEGER GdipSaveImageToFile IN gdiplus.DLL ;

INTEGER nImage, STRING wFilename, STRING qEncoder, INTEGER nEncoderParamsPtr DECLARE Long GdipDisposeImage IN Gdiplus.dll Long nativeImage

DECLARE INTEGER GdipCreateBitmapFromScan0 IN gdiplus.DLL ;

INTEGER nWidth, INTEGER nHeight, INTEGER nStride,INTEGER nPixelFormat,; STRING @ cScan0, INTEGER @ nImage

DECLARE INTEGER GdipGetImageHeight IN gdiplus INTEGER img,INTEGER @imgheight

DECLARE INTEGER GdipGetImageWidth IN gdiplus INTEGER img,INTEGER @imgwidth

DECLARE INTEGER GdipGetImageGraphicsContext IN gdiplus.DLL INTEGER nImage,INTEGER @nGraphics DECLARE INTEGER GdipDrawImageRect IN gdiplus.DLL ;

INTEGER nGraphics, INTEGER nImage, SINGLE,SINGLE,SINGLE,SINGLE

STORE 0 TO uHwnd,uHeight,uWidth,nBitmap,nGraphics

lqEncoderClsID_JPG=0h01F47C55041AD3119A730000F81EF32E

GDIPLUS_PIXELFORMAT_32bppARGB=0x0026200A

xdpi=350&&水平分辨率

ydpi=350&&垂直分辨率

Sourcefile=”旧图片.jpg”

Newfile=”新图片.jpg”

GdipLoadImageFromFile(STRCONV(Sourcefile+0h00,5),@uhwnd)

GdipGetImageHeight(uhwnd,@uHeight)

GdipGetImageWidth(uhwnd,@uWidth)

GdipCreateBitmapFromScan0(uWidth,uHeight,0,GDIPLUS_PIXELFORMAT_32bppARGB,0,@nBitmap) GdipGetImageGraphicsContext(nBitmap,@nGraphics)

GdipBitmapSetResolution(nBitmap,xdpi,ydpi)

GdipDrawImageRect(nGraphics,uHwnd,0,0,uWidth,uHeight)

GdipSaveImageToFile(nBitmap,STRCONV(Newfile +0h00,5),lqEncoderClsID_JPG,0)

GdipDisposeImage(uhwnd)

GdipDisposeImage(nBitmap)