XSImage, XSImageCreate, XSImageDestroy, XSImage2Pixmap

DESCRIPTION

XSImage is a typedef to a complex struct of private and public variables and describe a bitmapped color or grayscale imagem, with data organization independent of screen:

	img->name		string with image name
	img->width		image width in pixels
	img->height		image height in pixels
	img->channels		number of color channels
	img->format		image format
	img->data		pointer to image buffer with size width*height*channels
	img->filter		pointer to a list of filters.
	

Valid image formats are:

	XS_IMAGE_RGB24		24 bit color image (big-endian RGB)
	XS_IMAGE_BGR24		24 bit color image (litle-endian RGB)
	XS_IMAGE_RGB32		32 bit color image (big-endian, with alpha)
	XS_IMAGE_CMYK		32 bit color image (color complement)
	XS_IMAGE_GRAY		8 bit grayscale 
	

The number of channels is 1 for XS_IMAGE_GRAY, 3 for XS_IMAGE_RGB24 and XS_IMAGE_BGR24 and 4 for XS_IMAGE_ARGB32 and XS_IMAGE_CMYK.

For any color channel, you must have a level table linked in the filter pointer. For example, XS_IMAGE_RGB24 is a three channel image format, then you have three level tables in the filter list:

	img->filter[0]		is the level table for R channel
	img->filter[1]		is the level table for G channel	
	img->filter[2]		is the level table for B channel
	

All XSImage objects must be created by XSImageCreate and destroyed by XSImageDestroy. A XSImage object can be converted to a XSPixmap object with XSImage2Pixmap function.

XSImage2Pixmap will convert the device independent bitmap stored in a XSImage object to a device dependent XSPixmap. A XSPixmap object is a client/server object and XSImage2Pixmap will update the image in the server and in the client side.

Example

#include 
#include 
#include 
#include 
#include 

XSImage  *image;
XSPixmap *pixmap;

XSImage *readimage(char *name) {

	XSImage *aux=NULL;
	FILE 	*fp;
	char 	tmp[80],format[80],*data;
	int 	width,height,max;
	
	fp=fopen(name,"r");
	
	if(fp) {

		fgets(format,80,fp);

		if(!strncmp(format,"P5",2)) {
		
			while(fgets(tmp,80,fp)) if(tmp[0]!='#') break;
			sscanf(tmp,"%d %d",&width,&height);
			while(fgets(tmp,80,fp)) if(tmp[0]!='#') break;
			sscanf(tmp,"%d",&max);
			data=(char *)malloc(width*height);
			fread(data,1,width*height,fp);
			fclose(fp);
		
			if((aux=XSImageCreate(width,height,data,XS_IMAGE_GRAY))) aux->name=name;
		}
				
		if(!strncmp(format,"P6",2)) {
		
			while(fgets(tmp,80,fp)) if(tmp[0]!='#') break;
			sscanf(tmp,"%d %d",&width,&height);
			while(fgets(tmp,80,fp)) if(tmp[0]!='#') break;
			sscanf(tmp,"%d",&max);
			data=(char *)malloc(width*height*3);
			fread(data,1,width*height*3,fp);
			fclose(fp);
		
			if((aux=XSImageCreate(width,height,data,XS_IMAGE_RGB24))) aux->name=name;
		}
	}
	return aux;
}

void w1oncreate(XSWidget *wid) {
	
	XSWidgetCreate(wid);
	
	pixmap=XSPixmapCreate(wid,image->width,image->height,NULL,XS_PIXMAP_XSHM);

	XSImage2Pixmap(wid,image,pixmap,True);

	XSetWindowBackgroundPixmap(wid->display,wid->window,pixmap->pixmap);
	XClearWindow(wid->display,wid->window);

	wid->on.create=NULL;
}

int main(int argc,char **argv) {

	XSWidget *d1,*w1;

	if(!(image=readimage(argv[1]))) return -1;

	fprintf(stderr,
		"sucess: %dx%d pixels read from %s (%s)\n",
		image->width,
		image->height,
		image->name,
		image->format==XS_IMAGE_RGB24?"RGB24":"GRAY");
		
	d1=XSDesktop(getenv("DISPLAY"),argv,argc);
	w1=XSWindow(d1,0,0,image->width,image->height,image->name);

	w1->on.event[KeyPress]=XSWindowClose;
	w1->on.create=w1oncreate;
	
	while(XSCheckEvent(d1,XS_BLOCK));

	return 0;
}