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Old 11-06-2009, 12:17 AM   #1
ericshliao
Guru
ericshliao will become famous soon enoughericshliao will become famous soon enoughericshliao will become famous soon enoughericshliao will become famous soon enoughericshliao will become famous soon enoughericshliao will become famous soon enough
 
Posts: 976
Karma: 687
Join Date: Nov 2007
Device: Dell X51v; iLiad v2
What's wrong with my C code?

I have a small program (not really executable, just for experiement):
Code:
#include <glib.h>
#include <gdk-pixbuf/gdk-pixbuf.h>
//#include <glib/gi18n-lib.h>
#include <string.h>
#include <libdjvu/ddjvuapi.h>

typedef struct _DjvuDocument DjvuDocument;

typedef struct _EvRenderContext EvRenderContext;

struct _DjvuDocument {
	GObject           parent_instance;

	ddjvu_context_t  *d_context;
	ddjvu_document_t *d_document;
	ddjvu_format_t   *d_format;
	ddjvu_format_t   *thumbs_format;

	gchar            *uri;

        /* PS exporter */
        gchar		 *ps_filename;
        GString 	 *opts;
};

struct _EvRenderContext
{
	GObject parent;
	
	//EvPage *page;
	gint    rotation;
	gdouble scale;
};

cairo_surface_t *djvu_document_render (DjvuDocument *djvu_document, int page_index)
{
	
	EvRenderContext *rc;
	
	cairo_surface_t *surface;
	gchar *pixels;
	gint   rowstride;
    ddjvu_rect_t rrect;
	ddjvu_rect_t prect;
	ddjvu_page_t *d_page;
	ddjvu_page_rotation_t rotation;
	double page_width, page_height, tmp;
	static const cairo_user_data_key_t key;

	d_page = ddjvu_page_create_by_pageno (djvu_document->d_document, page_index);
	
	while (!ddjvu_page_decoding_done (d_page))
		djvu_handle_events(djvu_document, TRUE, NULL);

	page_width = ddjvu_page_get_width (d_page) * rc->scale * SCALE_FACTOR + 0.5;
	page_height = ddjvu_page_get_height (d_page) * rc->scale * SCALE_FACTOR + 0.5;
	
	switch (rc->rotation) {
	        case 90:
			rotation = DDJVU_ROTATE_90;
			tmp = page_height;
			page_height = page_width;
			page_width = tmp;
			
			break;
	        case 180:
			rotation = DDJVU_ROTATE_180;
			
			break;
	        case 270:
			rotation = DDJVU_ROTATE_270;
			tmp = page_height;
			page_height = page_width;
			page_width = tmp;
			
			break;
	        default:
			rotation = DDJVU_ROTATE_0;
	}
///#ifdef HAVE_CAIRO_FORMAT_STRIDE_FOR_WIDTH
	rowstride = cairo_format_stride_for_width (CAIRO_FORMAT_RGB24, page_width);
//#else
//	rowstride = page_width * 4;
//#endif
	pixels = (gchar *) g_malloc (page_height * rowstride);
	surface = cairo_image_surface_create_for_data ((guchar *)pixels,
						       CAIRO_FORMAT_RGB24,
						       page_width,
						       page_height,
						       rowstride);
	cairo_surface_set_user_data (surface, &key,
				     pixels, (cairo_destroy_func_t)g_free);
	prect.x = 0;
	prect.y = 0;
	prect.w = page_width;
	prect.h = page_height;
	rrect = prect;

	ddjvu_page_set_rotation (d_page, rotation);
	
	ddjvu_page_render (d_page, DDJVU_RENDER_COLOR,
			   &prect,
			   &rrect,
			   djvu_document->d_format,
			   rowstride,
			   pixels);

	return surface;
}

/*
static void
djvu_document_finalize (GObject *object)
{
	DjvuDocument *djvu_document = DJVU_DOCUMENT (object);

	if (djvu_document->d_document)
	    ddjvu_document_release (djvu_document->d_document);
	    
	if (djvu_document->opts)
	    g_string_free (djvu_document->opts, TRUE);

	if (djvu_document->ps_filename)
	    g_free (djvu_document->ps_filename);
	    
	ddjvu_context_release (djvu_document->d_context);
	ddjvu_format_release (djvu_document->d_format);
	ddjvu_format_release (djvu_document->thumbs_format);
	g_free (djvu_document->uri);
	
	G_OBJECT_CLASS (djvu_document_parent_class)->finalize (object);
}*/


int main()
{

    return 0;
}
I compiled it with:
gcc -o test lua-djview.c `pkg-config gtk+-2.0 ddjvuapi --libs --cflags`
using GCC4.1.2 in Debian 5.

And I alwasy got error message:
lua-djview.c:35: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘*’ token

Line 35 is marked in red.

The code is copied from source code of Evince with some modification. I know it must be a silly problem, but I just can't figure it out. Please help. Thanx.

Last edited by ericshliao; 11-06-2009 at 12:21 AM.
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Old 11-06-2009, 12:07 PM   #2
ericshliao
Guru
ericshliao will become famous soon enoughericshliao will become famous soon enoughericshliao will become famous soon enoughericshliao will become famous soon enoughericshliao will become famous soon enoughericshliao will become famous soon enough
 
Posts: 976
Karma: 687
Join Date: Nov 2007
Device: Dell X51v; iLiad v2
Sorry. Please ignore this problem. I found that the above code is not correct. Some variables undefinded, required headers not include...It's all my fault.

Added:
I am trying to create a djvu module for lua, so that I can create a djvu reader for iLiad using GTK+, instead of QTGui. It should save ram and loading time.

Evince uses Cairo to convert page image gererated from Djvulibre API to cairo_surface_t, then draw it on GdkWindow. That's really a clever way.

Last edited by ericshliao; 11-06-2009 at 12:31 PM.
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