Direct Calls to DLL > pdfMakeImage - convert selected pages to bitmaps

This special version of pdfMakeImage has been created to read PDF from a COM stream and write the created bitmap data to a COM stream.

function pdfMakeImageExt(

InStream : IUnknown; // Load PDF from here.

OutStream : IUnknown; // Save the image data here

filename : PWideChar; // Not used if InStream was specified

PageCount : PInteger; // Receives count of pages in PDF

password : PWideChar; // Password for the PDF

licname, lickey: PWideChar; liccode: Cardinal;

destpath: PWideChar; // Not used except to specify format

// if OutStream was specified (Use %d store page number)

frompage, to_page: Integer; // If OutStream was specified only one page is written

imageres : Integer; // The resolution, i.e. 200

// or HighWord=Height, LowWord=Width of desired image size.

// The bitmap will fit into the specified rectangle

imagemode : Integer // This is a bit field to specify the color and stream mode.

): Integer; stdcall;

or, in C++ syntax:

stdcall int pdfMakeImageExt(

IUnknown InStream, // Load PDF from here.

IUnknown OutStream, // Save the image data here

wchar *filename, // Not used if InStream was specified

int *PageCount, // Receives count of pages in PDF

wchar *password, // Password for the PDF

wchar *licname,

wchar *lickey,

int liccode,

wchar *destpath,; // Not used except to specify format

// if OutStream was specified (Use %d store page number)

int frompage,

int to_page: Integer, // If OutStream was specified only one page is written

int imageres, // The resolution, i.e. 200

// or HighWord=Height, LowWord=Width of desired image size.

// The bitmap will fit into the specified rectangle

int imagemode // This is a bit field to specify the color and stream mode.

);

All strings must be passed as wide character strings.

Example - C++Builder

res := pdfMakeImageExt(

InStream,

OutStream,

PWideChar(filename),

@PageCount,

'',

WPViewPDF_LicName,

WPViewPDF_LicKey,

WPViewPDF_LicCode,

PWideChar(os),

IOParams.ImageIndex+1,

ImageResolution,

);

imageres is the desired resolution for the created image, i.e. 200.

You can also specify the desired width and height of the bitmap inpixels. To do so, pass the width as high-word and the height as low-word of parameter imageres.

imagemode is used to specify the color depth.

1 - select BW Images

2 - Grayscale Image - default 24 bit color Image

otherwise a 24 bit color Image will be created

Bit 17-24 is used to specify the JPEG Compression (0-100)

Use the value 8 to create a gray scale image, 0 to create 24bit color.

InStream can be nil or a IStream reference. If it is a stream reference the PDF data will be loaded from there.

OutStream can be nil or a IStream reference. In the latter case the created bitmap data is written there. Filename must be still provided to make it possible to determine the desired image format. Possible file extensions are .BMP, .JPG, .PNG.

If the parameter imagemode is set to 32768 multiple images can be exported to a single stream with one call. The stream will use this header data:

INTEGER = total size of data (=StreamSize)

INTEGER = Count of Images

INTEGER[Count of Images] = Offset of each Image

If the Offset is 0, the image is empty.

The Length of the image data can be calculated as difference of the following, or, for the last image, the stream size