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Small optimization in djvu.c:drawPage() --- there is no need to create and destroy

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djvu pixel format on each redraw of the page as this can be done once on open and close
of the document. Also, set dither bits to 4 to help djvulibre choose the most
optimal dithering algorithm for the Kindle. Also, make coding style of "if(" -> "if ("
consistent (both instances were used, but "if (" was more frequent).
This commit is contained in:
Tigran Aivazian 2012-09-02 18:22:15 +01:00
parent b96f4f509f
commit 95be71c1e1
1 changed files with 31 additions and 30 deletions
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61
djvu.c
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@ -32,6 +32,7 @@
typedef struct DjvuDocument {
ddjvu_context_t *context;
ddjvu_document_t *doc_ref;
ddjvu_format_t *pixelformat;
} DjvuDocument;
typedef struct DjvuPage {
@ -93,6 +94,14 @@ static int openDocument(lua_State *L) {
return luaL_error(L, "cannot open DJVU file <%s>", filename);
}
doc->pixelformat = ddjvu_format_create(DDJVU_FORMAT_GREY8, 0, NULL);
if (! doc->pixelformat) {
return luaL_error(L, "cannot create DJVU pixelformat for <%s>", filename);
}
ddjvu_format_set_row_order(doc->pixelformat, 1);
ddjvu_format_set_y_direction(doc->pixelformat, 1);
ddjvu_format_set_ditherbits(doc->pixelformat, 4);
return 1;
}
@ -100,14 +109,18 @@ static int closeDocument(lua_State *L) {
DjvuDocument *doc = (DjvuDocument*) luaL_checkudata(L, 1, "djvudocument");
// should be save if called twice
if(doc->doc_ref != NULL) {
if (doc->doc_ref != NULL) {
ddjvu_document_release(doc->doc_ref);
doc->doc_ref = NULL;
}
if(doc->context != NULL) {
if (doc->context != NULL) {
ddjvu_context_release(doc->context);
doc->context = NULL;
}
if (doc->pixelformat != NULL) {
ddjvu_format_release(doc->pixelformat);
doc->pixelformat = NULL;
}
return 0;
}
@ -179,7 +192,7 @@ static int openPage(lua_State *L) {
DjvuDocument *doc = (DjvuDocument*) luaL_checkudata(L, 1, "djvudocument");
int pageno = luaL_checkint(L, 2);
if(pageno < 1 || pageno > ddjvu_document_get_pagenum(doc->doc_ref)) {
if (pageno < 1 || pageno > ddjvu_document_get_pagenum(doc->doc_ref)) {
return luaL_error(L, "cannot open page #%d, out of range (1-%d)", pageno, ddjvu_document_get_pagenum(doc->doc_ref));
}
@ -191,7 +204,7 @@ static int openPage(lua_State *L) {
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) {
if (! page->page_ref) {
return luaL_error(L, "cannot open page #%d", pageno);
}
@ -307,7 +320,7 @@ static int getPageText(lua_State *L) {
/* retrive one line entry */
se_line = miniexp_nth(i, sexp);
nr_word = miniexp_length(se_line);
if(nr_word == 0) {
if (nr_word == 0) {
continue;
}
@ -388,8 +401,8 @@ static int getPageText(lua_State *L) {
static int closePage(lua_State *L) {
DjvuPage *page = (DjvuPage*) luaL_checkudata(L, 1, "djvupage");
// should be save if called twice
if(page->page_ref != NULL) {
// should be safe if called twice
if (page->page_ref != NULL) {
ddjvu_page_release(page->page_ref);
page->page_ref = NULL;
}
@ -403,22 +416,14 @@ static int drawPage(lua_State *L) {
ddjvu_render_mode_t djvu_render_mode = (int) luaL_checkint(L, 6);
unsigned char adjusted_low[16], adjusted_high[16];
int i, adjust_pixels = 0;
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);*/
uint8_t *imagebuffer = malloc((bb->w)*(bb->h)+1);
/*printf("@page %d, @@zoom:%f, offset: (%d, %d)\n", page->num, dc->zoom, dc->offset_x, dc->offset_y);*/
/* fill pixel map with white color */
memset(imagebuffer, 0xFF, (bb->w)*(bb->h)+1);
/* render full page into rectangle specified by pagerect */
/*pagerect.x = luaL_checkint(L, 4);*/
/*pagerect.y = luaL_checkint(L, 5);*/
@ -429,13 +434,12 @@ static int drawPage(lua_State *L) {
/*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
* However, djvureader.lua handles offset differently. It uses 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).
@ -448,7 +452,7 @@ static int drawPage(lua_State *L) {
/*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.
* These four kinds of rotations can already be achieved by native system.
* So we don't set rotation here.
*/
@ -456,12 +460,12 @@ static int drawPage(lua_State *L) {
djvu_render_mode,
&pagerect,
&renderrect,
pixelformat,
page->doc->pixelformat,
bb->w,
imagebuffer);
uint8_t *bbptr = (uint8_t*)bb->data;
uint8_t *pmptr = (uint8_t*)imagebuffer;
uint8_t *bbptr = bb->data;
uint8_t *pmptr = imagebuffer;
int x, y;
/* if offset is positive, we are moving towards up and left. */
int x_offset = MAX(0, dc->offset_x);
@ -488,7 +492,7 @@ static int drawPage(lua_State *L) {
else
bbptr[x] = (high << 4) | low;
}
if(bb->w & 1) {
if (bb->w & 1) {
bbptr[x] = 255 - (pmptr[x*2] & 0xF0);
}
/* go to next line */
@ -497,9 +501,6 @@ static int drawPage(lua_State *L) {
}
free(imagebuffer);
pmptr = imagebuffer = NULL;
ddjvu_format_release(pixelformat);
return 0;
}