# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1446504128 -7200
# Node ID 2f02f100b20f3d2bacbc2f386b0af6c7e451b7a7

getting the window shape of another window

diff -r 000000000000 -r 2f02f100b20f .hgignore
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/.hgignore	Tue Nov 03 00:42:08 2015 +0200
@@ -0,0 +1,5 @@
+\.o$
+\.swp$
+\.d$
+\.ppm$
+^xgetshape$
diff -r 000000000000 -r 2f02f100b20f Makefile
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Makefile	Tue Nov 03 00:42:08 2015 +0200
@@ -0,0 +1,13 @@
+src = $(wildcard src/*.c)
+obj = $(src:.c=.o)
+bin = xgetshape
+
+CFLAGS = -pedantic -Wall -g
+LDFLAGS = -lGL -lX11 -lXext
+
+$(bin): $(obj)
+	$(CC) -o $@ $(obj) $(LDFLAGS)
+
+.PHONY: clean
+clean:
+	rm -f $(obj) $(bin)
diff -r 000000000000 -r 2f02f100b20f src/image.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/image.c	Tue Nov 03 00:42:08 2015 +0200
@@ -0,0 +1,122 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include "image.h"
+
+int image_create(struct image *img, int w, int h)
+{
+	img->width = w;
+	img->height = h;
+	if(!(img->pixels = malloc(w * h * 4))) {
+		return -1;
+	}
+	return 0;
+}
+
+void image_destroy(struct image *img)
+{
+	free(img->pixels);
+	img->pixels = 0;
+}
+
+int image_save(struct image *img, const char *rgbname, const char *aname)
+{
+	int i;
+	FILE *fp;
+	unsigned char *pptr;
+
+	if(rgbname) {
+		if(!(fp = fopen(rgbname, "wb"))) {
+			fprintf(stderr, "failed to open %s for writing: %s\n", rgbname, strerror(errno));
+			return -1;
+		}
+
+		fprintf(fp, "P6\n%d %d\n255\n", img->width, img->height);
+		pptr = img->pixels;
+		for(i=0; i<img->width * img->height; i++) {
+			fputc(*pptr++, fp);
+			fputc(*pptr++, fp);
+			fputc(*pptr++, fp);
+			++pptr;
+		}
+		fclose(fp);
+	}
+	if(aname) {
+		if(!(fp = fopen(aname, "wb"))) {
+			fprintf(stderr, "failed to open %s for writing: %s\n", rgbname, strerror(errno));
+			return -1;
+		}
+
+		fprintf(fp, "P6\n%d %d\n255\n", img->width, img->height);
+		pptr = img->pixels;
+		for(i=0; i<img->width * img->height; i++) {
+			int c = pptr[3];
+			pptr += 4;
+			fputc(c, fp);
+			fputc(c, fp);
+			fputc(c, fp);
+		}
+		fclose(fp);
+	}
+	return 0;
+}
+
+int image_clear(struct image *img, int r, int g, int b, int a)
+{
+	return image_fillrect(img, 0, 0, img->width, img->height, r, g, b, a);
+}
+
+int image_fillrect(struct image *img, int x, int y, int w, int h, int r, int g, int b, int a)
+{
+	int i, j;
+	unsigned char *pptr;
+
+	if(x < 0) {
+		w += x;
+		x = 0;
+	}
+	if(y < 0) {
+		h += y;
+		y = 0;
+	}
+	if(x + w >= img->width) {
+		w = img->width - x;
+	}
+	if(y + h >= img->height) {
+		h = img->height - y;
+	}
+	if(w <= 0 || h <= 0) {
+		return -1;
+	}
+
+	pptr = img->pixels + (y * img->width + x) * 4;
+	for(i=0; i<h; i++) {
+		for(j=0; j<w; j++) {
+			pptr[0] = r;
+			pptr[1] = g;
+			pptr[2] = b;
+			pptr[3] = a;
+			pptr += 4;
+		}
+		pptr += (img->width - w) * 4;
+	}
+	return 0;
+}
+
+int image_chess(struct image *img, int sz, int r0, int g0, int b0, int r1, int g1, int b1)
+{
+	int i, j;
+	unsigned char *pptr = img->pixels;
+
+	for(i=0; i<img->height; i++) {
+		for(j=0; j<img->width; j++) {
+			int chess = ((i / sz) & 1) == ((j / sz) & 1);
+			*pptr++ = chess ? r0 : r1;
+			*pptr++ = chess ? g0 : g1;
+			*pptr++ = chess ? b0 : b1;
+			*pptr++ = 255;
+		}
+	}
+	return 0;
+}
diff -r 000000000000 -r 2f02f100b20f src/image.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/image.h	Tue Nov 03 00:42:08 2015 +0200
@@ -0,0 +1,18 @@
+#ifndef IMAGE_H_
+#define IMAGE_H_
+
+struct image {
+	int width, height;
+	unsigned char *pixels;
+};
+
+int image_create(struct image *img, int w, int h);
+void image_destroy(struct image *img);
+
+int image_save(struct image *img, const char *rgbname, const char *aname);
+
+int image_clear(struct image *img, int r, int g, int b, int a);
+int image_fillrect(struct image *img, int x, int y, int w, int h, int r, int g, int b, int a);
+int image_chess(struct image *img, int sz, int r0, int g0, int b0, int r1, int g1, int b1);
+
+#endif	/* IMAGE_H_ */
diff -r 000000000000 -r 2f02f100b20f src/main.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main.c	Tue Nov 03 00:42:08 2015 +0200
@@ -0,0 +1,323 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <X11/Xlib.h>
+#include <X11/extensions/shape.h>
+#include <GL/glx.h>
+#include "image.h"
+#include "texture.h"
+
+void redraw(void);
+void reshape(int x, int y);
+int handle_event(XEvent *ev);
+
+/* X helper functions */
+Window create_window(int xsz, int ysz);
+void set_window_title(Window win, const char *title);
+int get_window_shape(Window win, struct image *img);
+
+Display *dpy;
+Window win;
+GLXContext ctx;
+int width, height;
+int mapped;
+int redisp_pending;
+Atom xa_wm_prot, xa_wm_del_win;
+struct image img;
+struct texture tex;
+struct texture chess_tex;
+float aspect;
+
+unsigned int target_xid = 0;
+
+int main(int argc, char **argv)
+{
+	int event_base, error_base;
+	char *endp;
+	struct image chess_img;
+
+	if(!argv[1]) {
+		fprintf(stderr, "pass the window id to use\n");
+		return 1;
+	}
+	if(!(target_xid = strtol(argv[1], &endp, 0))) {
+		fprintf(stderr, "invalid argument: %s\n", argv[1]);
+		return 1;
+	}
+
+	if(!(dpy = XOpenDisplay(0))) {
+		fprintf(stderr, "failed to open display\n");
+		return 1;
+	}
+	xa_wm_prot = XInternAtom(dpy, "WM_PROTOCOLS", False);
+	xa_wm_del_win = XInternAtom(dpy, "WM_DELETE_WINDOW", False);
+
+	if(!XShapeQueryExtension(dpy, &event_base, &error_base)) {
+		fprintf(stderr, "shape extension unsupported by this X server\n");
+		XCloseDisplay(dpy);
+		return 1;
+	}
+	if(get_window_shape(target_xid, &img) == -1) {
+		XCloseDisplay(dpy);
+		return 1;
+	}
+
+	if(!(win = create_window(1280, 800))) {
+		return 1;
+	}
+
+	image_texture(&tex, &img);
+
+	image_create(&chess_img, 256, 256);
+	image_chess(&chess_img, 8, 255, 128, 64, 64, 128, 255);
+	image_texture(&chess_tex, &chess_img);
+	image_destroy(&chess_img);
+
+	for(;;) {
+		XEvent ev;
+		XNextEvent(dpy, &ev);
+
+		if(handle_event(&ev) == -1) {
+			break;
+		}
+	}
+
+	XDestroyWindow(dpy, win);
+	XCloseDisplay(dpy);
+	return 0;
+}
+
+void redraw(void)
+{
+	glClearColor(0.4, 0.4, 0.4, 1);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	glMatrixMode(GL_MODELVIEW);
+	glLoadIdentity();
+
+	glEnable(GL_TEXTURE_2D);
+	glBindTexture(GL_TEXTURE_2D, chess_tex.id);
+
+
+	/* background */
+	glBegin(GL_QUADS);
+	glTexCoord2f(0, 0); glVertex2f(-aspect, -1);
+	glTexCoord2f(1, 0); glVertex2f(aspect, -1);
+	glTexCoord2f(1, 1); glVertex2f(aspect, 1);
+	glTexCoord2f(0, 1); glVertex2f(-aspect, 1);
+	glEnd();
+
+	/* draw the window shape */
+	glEnable(GL_BLEND);
+	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+	glBindTexture(GL_TEXTURE_2D, tex.id);
+	glMatrixMode(GL_TEXTURE);
+	glLoadIdentity();
+	glScalef((float)tex.width / (float)tex.tex_width,
+			(float)tex.height / (float)tex.tex_height,
+			1.0);
+
+	glMatrixMode(GL_MODELVIEW);
+	glPushMatrix();
+	glScalef(0.7, 0.7, 0.7);
+
+	/* shadow */
+	glPushMatrix();
+	glTranslatef(0.1, -0.1, 0);
+	glBegin(GL_QUADS);
+	glColor3f(0, 0, 0);
+	glTexCoord2f(0, 1); glVertex2f(-1, -1);
+	glTexCoord2f(1, 1); glVertex2f(1, -1);
+	glTexCoord2f(1, 0); glVertex2f(1, 1);
+	glTexCoord2f(0, 0); glVertex2f(-1, 1);
+	glEnd();
+	glPopMatrix();
+
+	/* window */
+	glBegin(GL_QUADS);
+	glColor3f(1, 1, 0);
+	glTexCoord2f(0, 1); glVertex2f(-1, -1);
+	glTexCoord2f(1, 1); glVertex2f(1, -1);
+	glTexCoord2f(1, 0); glVertex2f(1, 1);
+	glTexCoord2f(0, 0); glVertex2f(-1, 1);
+	glEnd();
+
+	glMatrixMode(GL_TEXTURE);
+	glLoadIdentity();
+	glMatrixMode(GL_MODELVIEW);
+	glPopMatrix();
+
+	glDisable(GL_BLEND);
+
+	glXSwapBuffers(dpy, win);
+}
+
+void reshape(int x, int y)
+{
+	aspect = (float)x / (float)y;
+	glViewport(0, 0, x, y);
+
+	glMatrixMode(GL_PROJECTION);
+	glLoadIdentity();
+	glScalef(1.0 / aspect, 1.0, 1.0);
+}
+
+int handle_event(XEvent *ev)
+{
+	switch(ev->type) {
+	case MapNotify:
+	case UnmapNotify:
+		mapped = ev->type == MapNotify ? 1 : 0;
+		break;
+
+	case Expose:
+		if(mapped && ev->xexpose.count == 0) {
+			redraw();
+		}
+		break;
+
+	case KeyPress:
+		{
+			KeySym sym = XLookupKeysym(&ev->xkey, 0);
+
+			switch(sym) {
+			case XK_Escape:
+				return -1;
+			}
+		}
+		break;
+
+	case ConfigureNotify:
+		if(ev->xconfigure.width != width || ev->xconfigure.height != height) {
+			width = ev->xconfigure.width;
+			height = ev->xconfigure.height;
+			reshape(width, height);
+		}
+		break;
+
+	case ClientMessage:
+		if(ev->xclient.message_type == xa_wm_prot) {
+			if(ev->xclient.data.l[0] == xa_wm_del_win) {
+				return -1;
+			}
+		}
+		break;
+	}
+	return 0;
+}
+
+Window create_window(int xsz, int ysz)
+{
+	Window w, root;
+	XVisualInfo *vis;
+	XClassHint chint;
+	XSetWindowAttributes xattr;
+	unsigned int evmask, xattr_mask;
+	int scr;
+	int glxattr[] = {
+		GLX_RGBA, GLX_DOUBLEBUFFER,
+		GLX_RED_SIZE, 8,
+		GLX_GREEN_SIZE, 8,
+		GLX_BLUE_SIZE, 8,
+		GLX_DEPTH_SIZE, 24,
+		GLX_USE_GL, 1,
+		None
+	};
+
+	scr = DefaultScreen(dpy);
+	root = RootWindow(dpy, scr);
+
+	if(!(vis = glXChooseVisual(dpy, scr, glxattr))) {
+		printf("failed to find a suitable visual\n");
+		return 0;
+	}
+	if(!(ctx = glXCreateContext(dpy, vis, 0, True))) {
+		XFree(vis);
+		return 0;
+	}
+
+	xattr.background_pixel = xattr.border_pixel = BlackPixel(dpy, scr);
+	xattr.colormap = XCreateColormap(dpy, root, vis->visual, AllocNone);
+	xattr_mask = CWColormap | CWBackPixel | CWBorderPixel;
+
+	if(!(w = XCreateWindow(dpy, root, 0, 0, xsz, ysz, 0, vis->depth, InputOutput,
+					vis->visual, xattr_mask, &xattr))) {
+		printf("failed to create window\n");
+		glXDestroyContext(dpy, ctx);
+		XFree(vis);
+		return 0;
+	}
+	XFree(vis);
+
+	evmask = StructureNotifyMask | VisibilityChangeMask | KeyPressMask |
+		ExposureMask;
+	XSelectInput(dpy, w, evmask);
+
+	XSetWMProtocols(dpy, w, &xa_wm_del_win, 1);
+
+	chint.res_name = chint.res_class = "xgetshape";
+	XSetClassHint(dpy, w, &chint);
+
+	set_window_title(w, "GL xgetshape");
+
+	glXMakeCurrent(dpy, w, ctx);
+	XMapWindow(dpy, w);
+	return w;
+}
+
+void set_window_title(Window win, const char *title)
+{
+	XTextProperty wm_name;
+	XStringListToTextProperty((char**)&title, 1, &wm_name);
+	XSetWMName(dpy, win, &wm_name);
+	XSetWMIconName(dpy, win, &wm_name);
+	XFree(wm_name.value);
+}
+
+int get_window_shape(Window win, struct image *img)
+{
+	Bool buse, cuse;
+	int bx, by, cx, cy;
+	unsigned int bw, bh, cw, ch;
+	int kind;
+	int x, y, w, h;
+	XRectangle *rects;
+	int i, rect_count, rect_order;
+
+	XShapeQueryExtents(dpy, win, &buse, &bx, &by, &bw, &bh,
+			&cuse, &cx, &cy, &bw, &bh);
+	if(cuse) {
+		x = cx;
+		y = cy;
+		w = cw;
+		h = ch;
+		kind = ShapeClip;
+	} else if(buse) {
+		x = bx;
+		y = by;
+		w = bw;
+		h = bh;
+		kind = ShapeBounding;
+	} else {
+		fprintf(stderr, "XShapeQueryExtents returned no extents\n");
+		return -1;
+	}
+
+	if(image_create(img, w, h) == -1) {
+		fprintf(stderr, "failed to create shape image (%dx%d)\n", w, h);
+		return -1;
+	}
+	image_clear(img, 0, 0, 0, 0);
+
+	if(!(rects = XShapeGetRectangles(dpy, win, kind, &rect_count, &rect_order))) {
+		fprintf(stderr, "failed to get the shape rectangles\n");
+		image_destroy(img);
+		return -1;
+	}
+
+	for(i=0; i<rect_count; i++) {
+		image_fillrect(img, rects[i].x, rects[i].y, rects[i].width, rects[i].height,
+				255, 255, 255, 255);
+	}
+	return 0;
+}
diff -r 000000000000 -r 2f02f100b20f src/texture.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/texture.c	Tue Nov 03 00:42:08 2015 +0200
@@ -0,0 +1,33 @@
+#include <GL/gl.h>
+#include "texture.h"
+
+static int next_pow2(int x);
+
+int image_texture(struct texture *tex, struct image *img)
+{
+	glGenTextures(1, &tex->id);
+	glBindTexture(GL_TEXTURE_2D, tex->id);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+	tex->width = img->width;
+	tex->height = img->height;
+	tex->tex_width = next_pow2(tex->width);
+	tex->tex_height = next_pow2(tex->height);
+
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex->tex_width, tex->tex_height, 0,
+			GL_RGBA, GL_UNSIGNED_BYTE, 0);
+	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, tex->width, tex->height,
+			GL_RGBA, GL_UNSIGNED_BYTE, img->pixels);
+	return 0;
+}
+
+static int next_pow2(int x)
+{
+	--x;
+	x |= x >> 1;
+	x |= x >> 2;
+	x |= x >> 4;
+	x |= x >> 8;
+	return x + 1;
+}
diff -r 000000000000 -r 2f02f100b20f src/texture.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/texture.h	Tue Nov 03 00:42:08 2015 +0200
@@ -0,0 +1,13 @@
+#ifndef TEXTURE_H_
+#define TEXTURE_H_
+
+#include "image.h"
+
+struct texture {
+	unsigned int id;
+	int width, height, tex_width, tex_height;
+};
+
+int image_texture(struct texture *tex, struct image *img);
+
+#endif	/* TEXTURE_H_ */