代码是用libpng和x11在窗口中显示一张图片，希望对你们有所帮助。
#include <X11/Xlib.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <png.h>
#include <X11/Xutil.h>
#include <X11/Xatom.h>
Window create_simple_window(Display* display, int width, int height, int x, int y)
{
int screen_num = DefaultScreen(display);
int win_border_width = 2;
Window win;
win = XCreateSimpleWindow(display, RootWindow(display, screen_num),
x, y, width, height, win_border_width,
BlackPixel(display, screen_num),
WhitePixel(display, screen_num));
/* make the window actually appear on the screen. */
XMapWindow(display, win);
/* flush all pending requests to the X server. */
XFlush(display);
return win;
}
GC create_gc(Display* display, Window win, int reverse_video)
{
GC gc; /* handle of newly created GC. */
unsigned long valuemask = 0; /* which values in 'values' to */
/* check when creating the GC. */
XGCValues values; /* initial values for the GC. */
unsigned int line_width = 2; /* line width for the GC. */
int line_style = LineSolid; /* style for lines drawing and */
int cap_style = CapButt; /* style of the line's edje and */
int join_style = JoinBevel; /* joined lines. */
int screen_num = DefaultScreen(display);
gc = XCreateGC(display, win, valuemask, &values);
if (gc < 0) {
fprintf(stderr, "XCreateGC: \n");
}
/* allocate foreground and background colors for this GC. */
if (reverse_video) {
XSetForeground(display, gc, WhitePixel(display, screen_num));
XSetBackground(display, gc, BlackPixel(display, screen_num));
}
else {
XSetForeground(display, gc, BlackPixel(display, screen_num));
XSetBackground(display, gc, WhitePixel(display, screen_num));
}
XSetLineAttributes(display, gc, line_width, line_style, cap_style, join_style);
XSetFillStyle(display, gc, FillSolid);
return gc;
}
static void TeardownPng (png_structp png, png_infop info)
{
if (png) {
png_infop *realInfo = (info? &info: NULL);
png_destroy_read_struct (&png, realInfo, NULL);
}
}
void LoadPng (FILE *file, unsigned char** data, char **clipData, unsigned int *width, unsigned int *height, unsigned int *rowbytes)
{
size_t size = 0, clipSize = 0;
png_structp png = NULL;
png_infop info = NULL;
unsigned char **rowPointers = NULL;
int depth = 0,
colortype = 0,
interlace = 0,
compression = 0,
filter = 0;
unsigned clipRowbytes = 0;
png = png_create_read_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
info = png_create_info_struct (png);
png_init_io (png, file);
png_read_info (png, info);
png_get_IHDR (png, info, (png_uint_32*)width, (png_uint_32*)height, &depth, &colortype, &interlace, &compression, &filter);
*rowbytes = png_get_rowbytes (png, info);
if (colortype == PNG_COLOR_TYPE_RGB) {
// X hates 24bit images - pad to RGBA
png_set_filler (png, 0xff, PNG_FILLER_AFTER);
*rowbytes = (*rowbytes * 4) / 3;
}
png_set_bgr (png);
*width = png_get_image_width (png, info);
*height = png_get_image_height (png, info);
size = *height * *rowbytes;
clipRowbytes = *rowbytes/32;
if (*rowbytes % 32)
++clipRowbytes;
clipSize = clipRowbytes * *height;
// This gets freed by XDestroyImage
*data = (unsigned char*) malloc (sizeof (png_byte) * size);
rowPointers = (unsigned char**) malloc (*height * sizeof (unsigned char*));
png_bytep cursor = *data;
int i=0,x=0,y=0;
for (i=0; i<*height; ++i, cursor += *rowbytes)
rowPointers[i] = cursor;
png_read_image (png, rowPointers);
*clipData = (char*) calloc (clipSize, sizeof(unsigned char));
if (colortype == PNG_COLOR_TYPE_RGB) {
memset (*clipData, 0xff, clipSize);
} else {
// Set up bitmask for clipping fully transparent areas
for (y=0; y<*height; ++y, cursor+=*rowbytes) {
for (x=0; x<*rowbytes; x+=4) {
// Set bit in mask when alpha channel is nonzero
if(rowPointers[y][x+3])
(*clipData)[(y*clipRowbytes) + (x/32)] |= (1 << ((x/4)%8));
}
}
}
TeardownPng (png, info);
free (rowPointers);
}
void
main(int argc, char* argv[])
{
Display* display;
int screen_num;
Window win;
unsigned int display_width, display_height;
unsigned int width, height;
char *display_name = getenv("DISPLAY");
GC gc;
/* in our window. */
unsigned width_ = 0, height_ = 0;
unsigned char *data = NULL;
char *clip = NULL;
unsigned rowbytes = 0;
unsigned long *image, *mask;
/* open connection with the X server. */
display = XOpenDisplay(display_name);
if (display == NULL) {
fprintf(stderr, "%s: cannot connect to X server '%s'\n",
argv[0], display_name);
exit(1);
}
/* get the geometry of the default screen for our display. */
screen_num = DefaultScreen(display);
display_width = DisplayWidth(display, screen_num);
display_height = DisplayHeight(display, screen_num);
/* make the new window occupy 1/9 of the screen's size. */
width = (display_width / 3);
height = (display_height / 3);
printf("window width - '%d'; height - '%d'\n", width, height);
win = create_simple_window(display, width, height, 0, 0);
gc = create_gc(display, win, 0);
XSync(display, False);
/* catch expose events */
XSelectInput(display, win, ExposureMask);
/* wait for the expose event */
XEvent ev;
XNextEvent(display, &ev);
// Load image
FILE *file = fopen ("./timg.png", "r");
if (!file)
return;
LoadPng (file, &data, &clip, &width_, &height_, &rowbytes);
if (!data)
return;
XImage *ximage = XCreateImage (display, DefaultVisual (display, DefaultScreen (display)), DefaultDepth(display, DefaultScreen (display)), ZPixmap, 0, (char*)data, width_, height_, 8, rowbytes);
if (ximage) {
XPutImage (display, win, gc, ximage, 0, 0, 0, 0, width_, height_);
} else {
free (data);
}
while(1)
{
XNextEvent(display, &ev);
if ( ev.type == Expose)
{
XPutImage (display, win, gc, ximage, 0, 0, 0, 0, width_, height_);
XFlush(display);
}
}
free (clip);
XFlush(display);
XSync(display, False);
XCloseDisplay(display);
}makefile
tupian: gtk3.c
gcc gtk3.c -g -o tupian -L/opt/X11/lib -lX11 -lXext `pkg-config --cflags --libs gtk+-3.0` -I `pkg-config libpng15 zlib --libs --cflags`需要安装libpng库和zlib。这是教程