juniorcamp/gfx.c

207 lines
4.7 KiB
C

/*
A simple graphics library for CSE 20211 by Douglas Thain
This work is licensed under a Creative Commons Attribution 4.0 International License. https://creativecommons.org/licenses/by/4.0/
For complete documentation, see:
http://www.nd.edu/~dthain/courses/cse20211/fall2013/gfx
Version 3, 11/07/2012 - Now much faster at changing colors rapidly.
Version 2, 9/23/2011 - Fixes a bug that could result in jerky animation.
*/
#include <X11/Xlib.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include "gfx.h"
/*
gfx_open creates several X11 objects, and stores them in globals
for use by the other functions in the library.
*/
static Display *gfx_display=0;
static Window gfx_window;
static GC gfx_gc;
static Colormap gfx_colormap;
static int gfx_fast_color_mode = 0;
/* These values are saved by gfx_wait then retrieved later by gfx_xpos and gfx_ypos. */
static int saved_xpos = 0;
static int saved_ypos = 0;
/* Open a new graphics window. */
void gfx_open( int width, int height, const char *title )
{
gfx_display = XOpenDisplay(0);
if(!gfx_display) {
fprintf(stderr,"gfx_open: unable to open the graphics window.\n");
exit(1);
}
Visual *visual = DefaultVisual(gfx_display,0);
if(visual && visual->class==TrueColor) {
gfx_fast_color_mode = 1;
} else {
gfx_fast_color_mode = 0;
}
int blackColor = BlackPixel(gfx_display, DefaultScreen(gfx_display));
int whiteColor = WhitePixel(gfx_display, DefaultScreen(gfx_display));
gfx_window = XCreateSimpleWindow(gfx_display, DefaultRootWindow(gfx_display), 0, 0, width, height, 0, blackColor, blackColor);
XSetWindowAttributes attr;
attr.backing_store = Always;
XChangeWindowAttributes(gfx_display,gfx_window,CWBackingStore,&attr);
XStoreName(gfx_display,gfx_window,title);
XSelectInput(gfx_display, gfx_window, StructureNotifyMask|KeyPressMask|ButtonPressMask);
XMapWindow(gfx_display,gfx_window);
gfx_gc = XCreateGC(gfx_display, gfx_window, 0, 0);
gfx_colormap = DefaultColormap(gfx_display,0);
XSetForeground(gfx_display, gfx_gc, whiteColor);
// Wait for the MapNotify event
for(;;) {
XEvent e;
XNextEvent(gfx_display, &e);
if (e.type == MapNotify)
break;
}
}
/* Draw a single point at (x,y) */
void gfx_point( int x, int y )
{
XDrawPoint(gfx_display,gfx_window,gfx_gc,x,y);
}
/* Draw a line from (x1,y1) to (x2,y2) */
void gfx_line( int x1, int y1, int x2, int y2 )
{
XDrawLine(gfx_display,gfx_window,gfx_gc,x1,y1,x2,y2);
}
/* Change the current drawing color. */
void gfx_color( int r, int g, int b )
{
XColor color;
if(gfx_fast_color_mode) {
/* If this is a truecolor display, we can just pick the color directly. */
color.pixel = ((b&0xff) | ((g&0xff)<<8) | ((r&0xff)<<16) );
} else {
/* Otherwise, we have to allocate it from the colormap of the display. */
color.pixel = 0;
color.red = r<<8;
color.green = g<<8;
color.blue = b<<8;
XAllocColor(gfx_display,gfx_colormap,&color);
}
XSetForeground(gfx_display, gfx_gc, color.pixel);
}
/* Clear the graphics window to the background color. */
void gfx_clear()
{
XClearWindow(gfx_display,gfx_window);
}
/* Change the current background color. */
void gfx_clear_color( int r, int g, int b )
{
XColor color;
color.pixel = 0;
color.red = r<<8;
color.green = g<<8;
color.blue = b<<8;
XAllocColor(gfx_display,gfx_colormap,&color);
XSetWindowAttributes attr;
attr.background_pixel = color.pixel;
XChangeWindowAttributes(gfx_display,gfx_window,CWBackPixel,&attr);
}
int gfx_event_waiting()
{
XEvent event;
gfx_flush();
while (1) {
if(XCheckMaskEvent(gfx_display,-1,&event)) {
if(event.type==KeyPress) {
XPutBackEvent(gfx_display,&event);
return 1;
} else if (event.type==ButtonPress) {
XPutBackEvent(gfx_display,&event);
return 1;
} else {
return 0;
}
} else {
return 0;
}
}
}
/* Wait for the user to press a key or mouse button. */
char gfx_wait()
{
XEvent event;
gfx_flush();
while(1) {
XNextEvent(gfx_display,&event);
if(event.type==KeyPress) {
saved_xpos = event.xkey.x;
saved_ypos = event.xkey.y;
return XLookupKeysym(&event.xkey,0);
} else if(event.type==ButtonPress) {
saved_xpos = event.xkey.x;
saved_ypos = event.xkey.y;
return event.xbutton.button;
}
}
}
/* Return the X and Y coordinates of the last event. */
int gfx_xpos()
{
return saved_xpos;
}
int gfx_ypos()
{
return saved_ypos;
}
/* Flush all previous output to the window. */
void gfx_flush()
{
XFlush(gfx_display);
}