koreader/djvu.c

/*
    KindlePDFViewer: DjvuLibre abstraction for Lua
    Copyright (C) 2011 Hans-Werner Hilse <hilse@web.de>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
#include <libdjvu/ddjvuapi.h>

#include "string.h"
#include "blitbuffer.h"
#include "djvu.h"

#define MIN(a, b)      ((a) < (b) ? (a) : (b))
#define MAX(a, b)      ((a) > (b) ? (a) : (b))

/*@TODO check all the close method, ensure memories are freed  03.03 2012*/

typedef struct DjvuDocument {
	ddjvu_context_t *context;
	ddjvu_document_t *doc_ref;
	int pages;
} DjvuDocument;

typedef struct DjvuPage {
	int num;
	ddjvu_page_t *page_ref;
	ddjvu_pageinfo_t info;
	DjvuDocument *doc;
} DjvuPage;

typedef struct DrawContext {
	int rotate;
	double zoom;
	double gamma;
	int offset_x;
	int offset_y;
} DrawContext;


static int handle(lua_State *L, ddjvu_context_t *ctx, int wait)
{
	const ddjvu_message_t *msg;
	if (!ctx)
		return;
	if (wait)
		msg = ddjvu_message_wait(ctx);
	while ((msg = ddjvu_message_peek(ctx)))
	{
	  switch(msg->m_any.tag)
		{
		case DDJVU_ERROR:
			if (msg->m_error.filename) {
				return luaL_error(L, "ddjvu: %s\nddjvu: '%s:%d'\n", 
					msg->m_error.message, msg->m_error.filename, 
					msg->m_error.lineno);
			} else {
				return luaL_error(L, "ddjvu: %s\n", msg->m_error.message);
			}
		default:
		  break;
		}
	  ddjvu_message_pop(ctx);
	}

	return 0;
}

static int openDocument(lua_State *L) {
	const char *filename = luaL_checkstring(L, 1);
	/*const char *password = luaL_checkstring(L, 2);*/

	DjvuDocument *doc = (DjvuDocument*) lua_newuserdata(L, sizeof(DjvuDocument));
	luaL_getmetatable(L, "djvudocument");
	lua_setmetatable(L, -2);

	doc->context = ddjvu_context_create("DJVUReader");
	if (! doc->context) {
		return luaL_error(L, "cannot create context.");
	}

	doc->doc_ref = ddjvu_document_create_by_filename(doc->context, filename, TRUE);
	while (! ddjvu_document_decoding_done(doc->doc_ref))
		handle(L, doc->context, True);
	if (! doc->doc_ref) {
		return luaL_error(L, "cannot open DJVU file <%s>", filename);
	}

	doc->pages = ddjvu_document_get_pagenum(doc->doc_ref);
	return 1;
}

static int closeDocument(lua_State *L) {
	DjvuDocument *doc = (DjvuDocument*) luaL_checkudata(L, 1, "djvudocument");
	if(doc->doc_ref != NULL) {
		ddjvu_document_release(doc->doc_ref);
		doc->doc_ref = NULL;
	}
	if(doc->context != NULL) {
		ddjvu_context_release(doc->context);
		doc->context = NULL;
	}
	return 0;
}

static int getNumberOfPages(lua_State *L) {
	DjvuDocument *doc = (DjvuDocument*) luaL_checkudata(L, 1, "djvudocument");
	lua_pushinteger(L, doc->pages);
	return 1;
}

/* not supported yet, so return empty table */
static int getTableOfContent(lua_State *L) {
	/*int count = 1;*/

	DjvuDocument *doc = (DjvuDocument*) luaL_checkudata(L, 1, "djvudocument");
	/*ol = djvu_load_outline(doc->doc_ref);*/

	lua_newtable(L);
	/*walkTableOfContent(L, ol, &count, 0);*/
	return 1;
}

static int newDrawContext(lua_State *L) {
	int rotate = luaL_optint(L, 1, 0);
	double zoom = luaL_optnumber(L, 2, (double) 1.0);
	int offset_x = luaL_optint(L, 3, 0);
	int offset_y = luaL_optint(L, 4, 0);
	double gamma = luaL_optnumber(L, 5, (double) -1.0);

	DrawContext *dc = (DrawContext*) lua_newuserdata(L, sizeof(DrawContext));
	dc->rotate = rotate;
	dc->zoom = zoom;
	dc->offset_x = offset_x;
	dc->offset_y = offset_y;
	dc->gamma = gamma;


	luaL_getmetatable(L, "drawcontext");
	lua_setmetatable(L, -2);

	return 1;
}

static int dcSetOffset(lua_State *L) {
	DrawContext *dc = (DrawContext*) luaL_checkudata(L, 1, "drawcontext");
	dc->offset_x = luaL_checkint(L, 2);
	dc->offset_y = luaL_checkint(L, 3);
	return 0;
}

static int dcGetOffset(lua_State *L) {
	DrawContext *dc = (DrawContext*) luaL_checkudata(L, 1, "drawcontext");
	lua_pushinteger(L, dc->offset_x);
	lua_pushinteger(L, dc->offset_y);
	return 2;
}

static int dcSetRotate(lua_State *L) {
	DrawContext *dc = (DrawContext*) luaL_checkudata(L, 1, "drawcontext");
	dc->rotate = luaL_checkint(L, 2);
	return 0;
}

static int dcSetZoom(lua_State *L) {
	DrawContext *dc = (DrawContext*) luaL_checkudata(L, 1, "drawcontext");
	dc->zoom = luaL_checknumber(L, 2);
	return 0;
}

static int dcGetRotate(lua_State *L) {
	DrawContext *dc = (DrawContext*) luaL_checkudata(L, 1, "drawcontext");
	lua_pushinteger(L, dc->rotate);
	return 1;
}

static int dcGetZoom(lua_State *L) {
	DrawContext *dc = (DrawContext*) luaL_checkudata(L, 1, "drawcontext");
	lua_pushnumber(L, dc->zoom);
	return 1;
}

static int dcSetGamma(lua_State *L) {
	DrawContext *dc = (DrawContext*) luaL_checkudata(L, 1, "drawcontext");
	dc->gamma = luaL_checknumber(L, 2);
	return 0;
}

static int dcGetGamma(lua_State *L) {
	DrawContext *dc = (DrawContext*) luaL_checkudata(L, 1, "drawcontext");
	lua_pushnumber(L, dc->gamma);
	return 1;
}

static int openPage(lua_State *L) {
	ddjvu_status_t r;
	DjvuDocument *doc = (DjvuDocument*) luaL_checkudata(L, 1, "djvudocument");
	int pageno = luaL_checkint(L, 2);

	if(pageno < 1 || pageno > doc->pages) {
		return luaL_error(L, "cannot open page #%d, out of range (1-%d)", pageno, doc->pages);
	}

	DjvuPage *page = (DjvuPage*) lua_newuserdata(L, sizeof(DjvuPage));
	luaL_getmetatable(L, "djvupage");
	lua_setmetatable(L, -2);

	/* djvulibre counts page starts form 0 */
	page->page_ref = ddjvu_page_create_by_pageno(doc->doc_ref, pageno - 1);
	while (! ddjvu_page_decoding_done(page->page_ref))
		handle(L, doc->context, TRUE);
	if(! page->page_ref) {
		return luaL_error(L, "cannot open page #%d", pageno);
	}

	page->doc = doc;
	page->num = pageno;

	/* djvulibre counts page starts form 0 */
	while((r=ddjvu_document_get_pageinfo(doc->doc_ref, pageno - 1, 
										&(page->info)))<DDJVU_JOB_OK)
		handle(L, doc->context, TRUE);
	if (r>=DDJVU_JOB_FAILED)
		return luaL_error(L, "cannot get page #%d information", pageno);

	return 1;
}

/* get page size after zoomed */
static int getPageSize(lua_State *L) {
	DjvuPage *page = (DjvuPage*) luaL_checkudata(L, 1, "djvupage");
	DrawContext *dc = (DrawContext*) luaL_checkudata(L, 2, "drawcontext");

	lua_pushnumber(L, dc->zoom * page->info.width);
	lua_pushnumber(L, dc->zoom * page->info.height);

	return 2;
}

/* unsupported so fake it */
static int getUsedBBox(lua_State *L) {
	DjvuPage *page = (DjvuPage*) luaL_checkudata(L, 1, "djvupage");

	lua_pushnumber(L, (double)0.01);
	lua_pushnumber(L, (double)0.01);
	lua_pushnumber(L, (double)-0.01);
	lua_pushnumber(L, (double)-0.01);

	return 4;
}

static int closePage(lua_State *L) {
	DjvuPage *page = (DjvuPage*) luaL_checkudata(L, 1, "djvupage");
	if(page->page_ref != NULL) {
		ddjvu_page_release(page->page_ref);
		page->page_ref = NULL;
	}
	return 0;
}

static int drawPage(lua_State *L) {
	DjvuPage *page = (DjvuPage*) luaL_checkudata(L, 1, "djvupage");
	DrawContext *dc = (DrawContext*) luaL_checkudata(L, 2, "drawcontext");
	BlitBuffer *bb = (BlitBuffer*) luaL_checkudata(L, 3, "blitbuffer");

	ddjvu_format_t *pixelformat;
	ddjvu_rect_t pagerect, renderrect;
	uint8_t *imagebuffer = NULL;

	imagebuffer = malloc((bb->w)*(bb->h)+1);
	/* fill pixel map with white color */
	memset(imagebuffer, 0xFF, (bb->w)*(bb->h)+1);

	pixelformat = ddjvu_format_create(DDJVU_FORMAT_GREY8, 0, NULL);
	ddjvu_format_set_row_order(pixelformat, 1);
	ddjvu_format_set_y_direction(pixelformat, 1);
	ddjvu_format_set_gamma(pixelformat, dc->gamma);
	/*ddjvu_format_set_ditherbits(dc->pixelformat, 2);*/

	/*printf("@page %d, @@zoom:%f, offset: (%d, %d)\n", page->num, dc->zoom, dc->offset_x, dc->offset_y);*/

	/* render full page into rectangle specified by pagerect */
	/*pagerect.x = luaL_checkint(L, 4);*/
	/*pagerect.y = luaL_checkint(L, 5);*/
	pagerect.x = 0;
	pagerect.y = 0;
	pagerect.w = page->info.width * dc->zoom;
	pagerect.h = page->info.height * dc->zoom;

	/*printf("--pagerect--- (x: %d, y: %d), w: %d, h: %d.\n", 0, 0, pagerect.w, pagerect.h);*/


	/* copy pixels area from pagerect specified by renderrect.

	 * ddjvulibre library does not support negative offset, positive offset 
	 * means moving towards right and down.
	 *
	 * However, djvureader.lua handles offset differently. It use negative 
	 * offset to move right and down while positive offset to move left 
	 * and up. So we need to handle positive offset manually when copying 
	 * imagebuffer to blitbuffer (framebuffer). 
	 */
	renderrect.x = MAX(-dc->offset_x, 0);
	renderrect.y = MAX(-dc->offset_y, 0);
	renderrect.w = MIN(pagerect.w - renderrect.x, bb->w);
	renderrect.h = MIN(pagerect.h - renderrect.y, bb->h);

	/*printf("--renderrect--- (%d, %d), w:%d, h:%d\n", renderrect.x, renderrect.y, renderrect.w, renderrect.h);*/

	/* ddjvulibre library only supports rotation of 0, 90, 180 and 270 degrees. 
	 * This four kinds of rotations can already be achieved by native system.
	 * So we don't set rotation here.
	 */

	ddjvu_page_render(page->page_ref,
			DDJVU_RENDER_COLOR,
			&pagerect,
			&renderrect,
			pixelformat,
			bb->w,
			imagebuffer);

	uint8_t *bbptr = (uint8_t*)bb->data;
	uint8_t *pmptr = (uint8_t*)imagebuffer;
	int x, y;
	/* if offset is positive, we are moving towards up and left. */
	int x_offset = MAX(0, dc->offset_x);
	int y_offset = MAX(0, dc->offset_y);

	bbptr += bb->pitch * y_offset;
	for(y = y_offset; y < bb->h; y++) {
		/* bbptr's line width is half of pmptr's */
		for(x = x_offset/2; x < (bb->w / 2); x++) {
			bbptr[x] = 255 - (((pmptr[x*2 + 1 - x_offset] & 0xF0) >> 4) | 
								(pmptr[x*2 - x_offset] & 0xF0));
		}
		if(bb->w & 1) {
			bbptr[x] = 255 - (pmptr[x*2] & 0xF0);
		}
		/* go to next line */
		bbptr += bb->pitch;
		pmptr += bb->w;
	}

	free(imagebuffer);
	pmptr = imagebuffer = NULL;
	ddjvu_format_release(pixelformat);

	return 0;
}

static const struct luaL_reg djvu_func[] = {
	{"openDocument", openDocument},
	{"newDC", newDrawContext},
	{NULL, NULL}
};

static const struct luaL_reg djvudocument_meth[] = {
	{"openPage", openPage},
	{"getPages", getNumberOfPages},
	{"getTOC", getTableOfContent},
	{"close", closeDocument},
	{"__gc", closeDocument},
	{NULL, NULL}
};

static const struct luaL_reg djvupage_meth[] = {
	{"getSize", getPageSize},
	{"getUsedBBox", getUsedBBox},
	{"close", closePage},
	{"__gc", closePage},
	{"draw", drawPage},
	{NULL, NULL}
};

static const struct luaL_reg drawcontext_meth[] = {
	{"setRotate", dcSetRotate},
	{"getRotate", dcGetRotate},
	{"setZoom", dcSetZoom},
	{"getZoom", dcGetZoom},
	{"setOffset", dcSetOffset},
	{"getOffset", dcGetOffset},
	{"setGamma", dcSetGamma},
	{"getGamma", dcGetGamma},
	{NULL, NULL}
};

int luaopen_djvu(lua_State *L) {
	luaL_newmetatable(L, "djvudocument");
	lua_pushstring(L, "__index");
	lua_pushvalue(L, -2);
	lua_settable(L, -3);
	luaL_register(L, NULL, djvudocument_meth);
	lua_pop(L, 1);

	luaL_newmetatable(L, "djvupage");
	lua_pushstring(L, "__index");
	lua_pushvalue(L, -2);
	lua_settable(L, -3);
	luaL_register(L, NULL, djvupage_meth);
	lua_pop(L, 1);

	luaL_newmetatable(L, "drawcontext");
	lua_pushstring(L, "__index");
	lua_pushvalue(L, -2);
	lua_settable(L, -3);
	luaL_register(L, NULL, drawcontext_meth);
	lua_pop(L, 1);

	luaL_register(L, "djvu", djvu_func);
	return 1;
}