RESIZE IMAGES WITH VFP9 and GDI+

The function GetThumbnailImage can be used to get a resized image, but the result may come with less quality.

The sample below does the same thing, but creates an image with a better quality.

#DEFINE GdiPlus_PixelFormat_1BPPindexed      0x00030101
#DEFINE GdiPlus_PixelFormat_4BPPindexed      0x00030402
#DEFINE GdiPlus_PixelFormat_8BPPindexed      0x00030803
#DEFINE GdiPlus_PixelFormat_16BPPgrayscale   0x00101004
#DEFINE GdiPlus_PixelFormat_16BPPRGB555      0x00021005
#DEFINE GdiPlus_PixelFormat_16BPPRGB565      0x00021006
#DEFINE GdiPlus_PixelFormat_16BPPARGB1555    0x00061007
#DEFINE GdiPlus_PixelFormat_24BPPRGB         0x00021808
#DEFINE GdiPlus_PixelFormat_32BPPRGB         0x00022009
#DEFINE GdiPlus_PixelFormat_32BPPARGB        0x0026200a
#DEFINE GdiPlus_PixelFormat_32BPPpARGB       0x000e200b
#DEFINE GdiPlus_PixelFormat_48BPPRGB         0x0010300c
#DEFINE GdiPlus_PixelFormat_64BPPpARGB       0x001c400e

LOCAL lcSource, lcDestination
m.lcSource = GETPICT("jpg;gif;bmp")
m.lcDestination = ADDBS(JUSTPATH(m.lcSource)) + "resized_" + JUSTSTEM(m.lcSource) + ".bmp"

LOCAL loImage AS gpImage OF ffc / _GdiPlus.vcx
m.loImage = NEWOBJECT("gpimage", HOME() + "ffc/_GdiPlus.vcx")
m.loImage.CreateFromFile(m.lcSource)

LOCAL loBitmap AS gpBitmap OF ffc / _GdiPlus.vcx
m.loBitmap = NEWOBJECT("gpbitmap", HOME() + "ffc/_GdiPlus.vcx")

LOCAL loGraphics AS gpGraphics OF HOME() + ffc / _GdiPlus.vcx
m.loGraphics = NEWOBJECT('gpgraphics',HOME() + 'ffc/_GdiPlus.vcx')

*** now we create a new image with
*** create method - creates a bitmap object.
*** syntax: ? this.create(tnwidth, tnheight[, tnpixelFormat])
*** tnpixelFormat, optional, one of GdiPlus_pixelFormat_* constants,
*** defaults to GdiPlus_pixelFormat_32BPPARGB.

LOCAL lnNewWidth, lnNewHeight
m.lnNewWidth = 640  && put here the desired width
m.lnNewHeight = 480 && put here the desired height

m.loBitmap.CREATE(m.lnNewWidth, m.lnNewHeight, GdiPlus_PixelFormat_32BPPpARGB)
*** the other constants are in the beginning of this code

m.loGraphics.CreateFromImage(m.loBitmap)
m.loGraphics.DrawImageScaled(m.loImage, 0, 0, m.lnNewWidth, m.lnNewHeight)
m.loBitmap.SaveToFile(m.lcDestination, "image/bmp")

RETURN

 

Update 04/08/2007

 

Below is another way to resize an image using the GetThumbnailImage function, shown by Craig Boyd in a UT thread:

LOCAL lcSource, lcDestination
m.lcSource = GETPICT()
m.lcDestination = "c:\" + JUSTFNAME(m.lcSource) && image will be saved on to c:\</font>
IF ! CreateThumbnail(m.lcSource, m.lcDestination, 85, 100)
    MESSAGEBOX("unable to create image")
ENDIF

FUNCTION CreateThumbnail(tcsource, tcdestination, tnwidth, tnheight)
    LOCAL llSuccess, loImage, loThumbImage
    m.llSuccess = .F.
    IF FILE(m.tcsource)
        m.loImage = NEWOBJECT('gpimage',HOME(1) + 'ffc\_gdiplus.vcx')
        m.loImage.CreateFromFile(m.tcsource)
        m.loThumbImage = m.loImage.getthumbnailimage(m.tnwidth, m.tnheight)
        IF TYPE("lothumbimage") = "o"
            m.llSuccess = m.loThumbImage.SaveToFile(m.tcdestination, "image/jpeg")
        ENDIF
    ENDIF
    RETURN m.llSuccess
ENDFUNC