convertRegionToPicture
IPicture
interface).
The rectangular region is specified by the x,y coordinates of its upper-left corner and its width and height - in bitmap coordinates, not PDF coordinates. That is, if the whole-page bitmap would have been 1000 pixels wide and 2000 pixels high, and you request a region with (x,y) = (0,0) and (w,h) = (1000,500), the resulting bitmap will be the top fourth of the page.
The arguments are:
page
= page numberregionX
,regionY
= upper-left corner of regionregionW
,regionH
= width and height of regiondpi
= resolution (dots per inch)color
= color setting - one of:imageMono
: 1-bit monochromeimageGray
: 8-bit grayscaleimageRGB
: 8-bit RGBimageDevNToRGB
: 8-bit RGB, rasterized in DeviceN and then converted to RGBimageGrayToMono
: 1-bit monochrome, rasterized in 8-bit grayscale and then converted to 1-bit
pdf.imageMono
, etc.
The imageDevNToRGB
mode produces RGB output like imageRGB
, but
does the rasterization in DeviceN (CMYK + spot colors) so overprint
previews will be more accurate.
The imageGrayToMono
mode does the rasterization in 8-bit grayscale
and converts to 1-bit monochrome at the end. This is useful for files
that use transparency – because 1-bit monochrome mode doesn't
support transparency.