[.. upper level ..]

Window functions

Manage window.

• Enumerations and Structures
  
• VG_POSITIONS
• VG_WINDOW_SCALES
• VG_WINDOW_SIZES
• struct VG_Position
• struct VG_Rect


• Opening and closing
  
• vg4->window->open()
  
  Open window.
• vg4->window->reopen()
  
  Reopen window.
• vg4->window->close()
  
  Close window.


• Window properties
  
• vg4->window->getparameters()
  
  Get parameters of the window.
• vg4->window->getsize()
  
  Get virtual size of the window.
• vg4->window->getbrightness()
  
  Get common window brightness.
• vg4->window->setbrightness()
  
  Set common window brightness.
• vg4->window->getattr()
  
  Get window attributes.
• vg4->window->setattr()
  
  Set window attributes.
• vg4->window->scale_params()
  
  Set scaling parameters.


• Modifying window contents
  
• vg4->window->clear()
  
  Clear window.
• vg4->window->copy()
  
  Copy image onto window.
• vg4->window->fill()
  
  Fill window with a color.
• vg4->window->draw_point()
  
  Draw a pixel onto window.
• vg4->window->draw_points()
  
  Draw pixels onto window.
• vg4->window->draw_line()
  
  Draw a line onto window.
• vg4->window->draw_rect()
  
  Draw a rectangle onto window.
• vg4->window->draw_circle()
  
  Draw a circle onto window.


• Miscellaneous window functions
  
• vg4->window->flush()
  
  Flush contents to window.
• vg4->window->shake()
  
  Set a short shaking of the window
• vg4->window->clone()
  
  Clone window contents into image.
• vg4->window->screenshot()
  
  Save a screenshot of the actual window to a file.


• Environment variables
  
• VG_IO_LIBRARY
  
  IO-library to load, e.g. "SDL2". Currently supported libraries: - SDL2 - SDL3 If empty use first found IO-library.
• VG_RENDERER
  
  Renderer to use, e.g. "opengl" or "software". Defaults to a suitable accelerated renderer.
• VG_NO_INFO
  
  Whether print no info messages to stderr. Values: - 0: print (default) - 1: print not
• VG_NO_WARNING
  
  Whether print no warning messages to stderr. Values: - 0: print (default) - 1: print not


• Environment variables for debugging
  
• VG_DUMP_ON_EXIT
  
  Whether show dumps when calling VG_dest(). - 0: no (default) - 1: yes, to stdout - 2: yes, to stderr
• VG_FILM_DUMP
  
  Concerning playing films. Values: - 0: play film (default) - 1: dump and play film - 2: only dump film

Example

example.c

/* open window and draw a circle, then again with window properties set to grey color */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <vgagames4.h>

int main(int argc, char **argv) {
  int winw, winh, radius;
  struct VG_ImagecopyAttrPixel wattr_pixel;

  (void)argc; (void)argv;

  /* initialize VgaGames library */
  if (!VG_init("window-example")) { exit(1); }

  /* open window with low size and best (integer) scaling */
  if (!vg4->window->open(VG_WINDOW_SIZE_LOW, VG_WINDOW_SCALE_BEST)) { VG_dest(); exit(1); }

  /* get (virtual) size of the window */
  vg4->window->getsize(&winw, &winh);

  /* +++ first draw a yellow circle onto a blue background +++ */

  /* clear window and fill it with blue color */
  vg4->window->clear();
  vg4->window->fill(VG_COLOR_BLUE);

  /* draw a yellow filled circle at the center of the window */
  radius = (winw > winh ? winh : winw) / 4;
  vg4->window->draw_circle(winw / 2, winh / 2, radius, VG_COLOR_YELLOW, VG_TRUE);

  /* flush window contents and wait 3 seconds */
  vg4->window->flush();
  sleep(3);

  /* +++ now set window to grey and draw the circle again +++ */

  /* set window attributes to grey color */
  VG_IMAGECOPY_ATTRPIXEL_DEFAULT(&wattr_pixel);
  wattr_pixel.pixelcolor = VG_PIXELCOLOR_GREY;
  vg4->window->setattr(&wattr_pixel);

  /* clear window and fill it with blue color */
  vg4->window->clear();
  vg4->window->fill(VG_COLOR_BLUE);

  /* draw a yellow filled circle at the center of the window */
  radius = (winw > winh ? winh : winw) / 4;
  vg4->window->draw_circle(winw / 2, winh / 2, radius, VG_COLOR_YELLOW, VG_TRUE);

  /* flush window contents and wait 3 seconds */
  vg4->window->flush();
  sleep(3);

  /* destroy and exit */
  VG_dest();
  exit(0);
}


Makefile

CFLAGS = -W -Wall -O2
VGAG_CFLAGS = `vgagames4-config --cflags`
VGAG_LIBS = `vgagames4-config --libs`

example: example.o
	$(CC) $(CFLAGS) example.o $(VGAG_LIBS) -o example

example.o: example.c
	$(CC) $(CFLAGS) $(VGAG_CFLAGS) -c example.c

clean:
	rm -f example example.o