[gs-devel] Questions on text extraction

[James Burton]

Hello,
  I'm working on a custom device that will produce a ping file, plus the 
extracted text.  After using the debugger to track what was happening in the 
pdfwrite driver, I actually got it to work, but I have to following 
questions:

1) In the text_begin() function, is this the correct way to get the Unicode? 
  Is there anything missing?  The documentation doc/Drivers.htm in the 
paragraph "Unicode support for high level devices" mentions using the 
"current subfont".  But I don't create a "a new instance of gs_text_enum_t" 
because I just grab the text and fall throught to the default text_begin 
function to do the real work.  Is something going to break?

MyDevice_text_begin(gx_device * dev, gs_imager_state * pis,
        	const gs_text_params_t * text, gs_font * font,
		gx_path * path, const gx_device_color * pdcolor,
		const gx_clip_path * pcpath,
		gs_memory_t * memory, gs_text_enum_t ** ppenum)
{
...
                for ( i=0; i<text->size; i++ )
                {
                    gs_char unicode;
		    gs_glyph glyph;

		    glyph = (*font->procs.encode_char)(font, (gs_char)text->data.bytes[i],
						       GLYPH_SPACE_NAME);

		    if (glyph != GS_NO_GLYPH)
		    {
			unicode = font->procs.decode_glyph(font, glyph);
                        if (unicode==GS_NO_CHAR)
	   		    myText[i]=text->data.bytes[i];
		        else
		            myText[i]=unicode&0xFF;
		    } else
			myText[i]=text->data.bytes[i];
...
    }
    code = gx_default_text_begin(dev, pis, text, font, path, pdcolor,
                                 pcpath, memory, ppenum);
done:
    return code;
}


2) Coupled with this, where changes in the lib/gs_pdfwr.ps file.  Basically, 
everthere there was a test to see if the device was "pdfwrite", I had to 
also put a test to see if the device was "MyDevice".  For example:

This:
  currentdevice .devicename /pdfwrite eq {

Was changed to this:

  currentdevice .devicename /pdfwrite eq
  currentdevice .devicename /MyDevice eq or {

Also, this:

  currentdevice .devicename /pdfwrite ne {

Was changed to this:

  currentdevice .devicename /pdfwrite ne
  currentdevice .devicename /MyDevice ne and {

I couldn't figure out how to create my own postscript file that would be 
included.  In fact, I tried my best, but couldn't find any source or 
postscript calling gs_pdfwr.ps in the source.  I knew it was being called, 
because if I renamed it, ghostscript would error.  What is the proceedure 
for adding a device specific postscript file?

James Burton

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