Attachment 135294 Details for Bug 103614 – small C program showing the bug, look at tag 'bug #3' in the source for details.

small C program showing the bug, look at tag 'bug #3' in the source for details.

cairo_xlib.c (text/x-csrc), 3.63 KB, created by Stefan on 2017-11-08 00:32:28 UTC

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Creator: Stefan

Created: 2017-11-08 00:32:28 UTC

Size: 3.63 KB

patch

obsolete

>/* File: cairo_xlib.c
> * sample program that uses cairo to put a png image into a Xlib window
> * 
> * Copyright (C) 2016 Stefan Frederik Schippers
> *
> * 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 2 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, write to the Free Software
> * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> * 
> * compile:
> * gcc -o cairo_xlib cairo_xlib.c $(pkg-config --libs --cflags cairo) -lX11
> */
>
>#include <stdio.h>
>#include <stdlib.h>
>#include <X11/Xlib.h>
>#include <cairo.h>
>#include <cairo-xlib.h>
>int main(int argc, char **argv)
>{
>   cairo_surface_t *sfc, *image;
>   cairo_t *ctx, *ctximage;
>   int screen, x, y, running, black, white;
>   Display *display;
>   Drawable window;
>   Visual *visual;
>   XEvent e;
>
>   if(argc != 2) return 1; /* must give a png file as argument */
>   image = cairo_image_surface_create_from_png(argv[1]); /* load png file */
>   //image=cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 600, 400);
>   x = cairo_image_surface_get_width (image);
>   y = cairo_image_surface_get_height (image);
>   printf("png image size: x=%d, y=%d\n", x, y);
>   ctximage = cairo_create(image);
>   cairo_set_line_width(ctximage, 4);
>   cairo_set_source_rgb(ctximage, 0.3, 0.7, 0.0);
>
>   /* bug #1: this line crosses the clip area (0,0, x, y) but is not displayed
>      unless you use smaller numbers (20000.) */
>   cairo_move_to(ctximage, -200000., -200000.);
>   cairo_line_to(ctximage, 200000., 200000.);
>   cairo_stroke(ctximage);
>   
>   
>   if((display = XOpenDisplay(NULL)) == NULL) return 1; /* create x11 window */
>   screen = DefaultScreen(display);
>   visual = DefaultVisual(display, screen);
>   black = BlackPixel(display, screen);
>   white = WhitePixel(display, screen);
>   window = XCreateSimpleWindow(display, DefaultRootWindow(display), 0, 0, x, y, CopyFromParent, white, white);
>   XSelectInput(display, window, StructureNotifyMask|ButtonPressMask | KeyPressMask | ExposureMask);
>   XMapWindow(display, window);
>
>   sfc = cairo_xlib_surface_create(display, window, visual, x, y);
>   ctx = cairo_create(sfc);
>   cairo_set_source_surface(ctx, image, 0., 0.); /* set png image as source */
>   for(running=1;running;) {
>      /* bug #2: cairo throws events with type=65 via XSendEvent
>         we get this event even if its not in the event mask.
>         Not a problem, simply ignore it */
>      XNextEvent(display, &e);
>      printf("loop: event type=%d\n", (int)e.type);
>      switch(e.type) {
>         case ConfigureNotify:
>            /* bug #3: sfc must have size bigger than image, either in x or y add one pixel
>               otherwise you get only a background screen */
>            cairo_xlib_surface_set_size(sfc, x, y);
>            printf("configure event: x=%d, y=%d\n", cairo_xlib_surface_get_width(sfc), cairo_xlib_surface_get_height(sfc));
>            break;
>         case Expose:
>            cairo_paint(ctx); /* paint window with png image */
>            break;
>         case KeyPress: /* exit */
>         case ButtonPress:
>            running = 0;
>            break;
>      }
>   }
>   cairo_destroy(ctx);
>   cairo_surface_destroy(sfc);
>   cairo_surface_destroy(image);
>   XCloseDisplay(display);
>   return 0;
>}

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