Draw border (frame) using xlib

Question

Is it possible to draw transparent window without title bar, close button, responses on mouse buttons using xlib. So just border with specific color and width? Something like

this orange rectangle is what I need to create. Also I'd like to have possibility to move, resize, close and make it flicking (change border's color on timer) programatically.

I managed to create transparent window without titlebar and draw rectangles on each side of the window to make border-effect:

#define W_WIDTH 640
#define W_HEIGHT 480

#define X_POS 100
#define Y_POS 120
#define BORDER_WIDTH 2

Display *dpy;
Window w;

XRectangle rectangles[4] =
    {
    { X_POS, Y_POS, W_WIDTH, BORDER_WIDTH },
    { X_POS, Y_POS, BORDER_WIDTH, W_HEIGHT },
    { X_POS, W_HEIGHT - BORDER_WIDTH, W_WIDTH, BORDER_WIDTH },
    { W_WIDTH - BORDER_WIDTH, Y_POS, BORDER_WIDTH, W_HEIGHT }
    };

int main(int argc, char *argv[])
{
    GC gc;
    XGCValues gcv;
    int run = 1;

    dpy = XOpenDisplay(NULL);

    XVisualInfo vinfo;
    XMatchVisualInfo(dpy, DefaultScreen(dpy), 32, TrueColor, &vinfo);
    XSetWindowAttributes attr;
    attr.colormap = XCreateColormap(dpy, DefaultRootWindow(dpy), vinfo.visual, AllocNone);

    w = XCreateWindow(dpy, DefaultRootWindow(dpy), X_POS, Y_POS,
                      W_WIDTH, W_HEIGHT, BORDER_WIDTH, vinfo.depth,
                      InputOutput, vinfo.visual, CWColormap | CWBorderPixel | CWBackPixel, &attr);
    XColor color;
    Colormap colormap;
    char orangeDark[] = "#FF8000";
    colormap = DefaultColormap(dpy, 0);
    XParseColor(dpy, colormap, orangeDark, &color);
    XAllocColor(dpy, colormap, &color);

    gcv.line_width = BORDER_WIDTH;
    gc = XCreateGC(dpy, w, GCLineWidth, &gcv);

    XSelectInput(dpy, w, ExposureMask);
    Atom window_type = XInternAtom(dpy, "_NET_WM_WINDOW_TYPE", False);
    long value = XInternAtom(dpy, "_NET_WM_WINDOW_TYPE_DOCK", False);
    XChangeProperty(dpy, w, window_type, XA_ATOM, 32, PropModeReplace, (unsigned char *) &value, 1);
    XMapWindow(dpy, w);
    XSync(dpy, False);

    while(run)
    {
        XEvent xe;
        XNextEvent(dpy, &xe);
        switch (xe.type)
        {
            case Expose:
                XSetForeground(dpy, gc, color.pixel);
                XDrawRectangles(dpy, w, gc, rectangles, 4);
                XFillRectangles(dpy, w, gc, rectangles, 4);
                XSync(dpy, False);
                break;
            default:
                break;
        }
    }

    XDestroyWindow(dpy, w);
    XCloseDisplay(dpy);

    return 0;
}

This code works almost fine except the thing, that my orange border is semitransparent and is almost invisible on light windows: Could you please tell how I need change my code to draw solid orange rectangles? Another variant I have is to draw transparent rectangle inside of orange window. But I didn't find any info in the Internet about how to do that.

Vinificator

Usually window border is handled by the Window Manager. So you probably don't want this border, instead you want a borderless window which has the rectangle inside its edges, and transparent center. – Yanirayank

Thanks. Then the second variant should be implemented. Could you please share examples how to make transparent center inside of my orange rectangle? – Vinificator

I don't have such an example. – Yanirayank

May be some links I can read to implement transparent center within my orange window? – Vinificator

@Vinificator #39906628 – Broadus

@JL2210, thanks for the reply, but unfortunately it isn't what I need...or may be it is, but I don't understand how can it solve my problem. Do you mean, that my window shouldn't be completely transparent? – Vinificator

Answer 1

Two main mistakes.

1. Not initializing attr and gcv to 0
2. Not using attr.colormap for color allocation

That should help:

#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xatom.h>

#define W_WIDTH 640
#define W_HEIGHT 480

#define X_POS 100
#define Y_POS 120
#define BORDER_WIDTH 2

int main(int argc, char *argv[]) {
    XRectangle rectangles[4] = {
        { X_POS, Y_POS, W_WIDTH, BORDER_WIDTH },
        { X_POS, Y_POS, BORDER_WIDTH, W_HEIGHT },
        { X_POS, W_HEIGHT - BORDER_WIDTH, W_WIDTH, BORDER_WIDTH },
        { W_WIDTH - BORDER_WIDTH, Y_POS, BORDER_WIDTH, W_HEIGHT }
    };
    Display *dpy = XOpenDisplay(NULL);
    XSetWindowAttributes attr = {0};
    XGCValues gcv = {0};
    XVisualInfo vinfo;
    GC gc;

    Window w;

    int run = 1;

    XMatchVisualInfo(dpy, DefaultScreen(dpy), 32, TrueColor, &vinfo);
    attr.colormap = XCreateColormap(dpy, DefaultRootWindow(dpy), vinfo.visual, AllocNone);

    XColor color;
    char orangeDark[] = "#FF8000";
    XParseColor(dpy, attr.colormap, orangeDark, &color);
    XAllocColor(dpy, attr.colormap, &color);

    w = XCreateWindow(dpy, DefaultRootWindow(dpy), X_POS, Y_POS,
                      W_WIDTH, W_HEIGHT, BORDER_WIDTH, vinfo.depth,
                      InputOutput, vinfo.visual, CWColormap | CWBorderPixel | CWBackPixel, &attr);

    gcv.line_width = BORDER_WIDTH;
    gc = XCreateGC(dpy, w, GCLineWidth, &gcv);

    XSelectInput(dpy, w, ExposureMask);
    long value = XInternAtom(dpy, "_NET_WM_WINDOW_TYPE_DOCK", False);
    XChangeProperty(dpy, w, XInternAtom(dpy, "_NET_WM_WINDOW_TYPE", False),
                    XA_ATOM, 32, PropModeReplace, (unsigned char *) &value, 1);
    XMapWindow(dpy, w);
    XSync(dpy, False);

    while(run) {
        XEvent xe;
        XNextEvent(dpy, &xe);
        switch (xe.type) {
            case Expose:
                XSetForeground(dpy, gc, color.pixel);
                XDrawRectangles(dpy, w, gc, rectangles, 4);
                XFillRectangles(dpy, w, gc, rectangles, 4);
                XSync(dpy, False);
                break;

            default:
                break;
        }
    }

    XDestroyWindow(dpy, w);
    XCloseDisplay(dpy);

    return 0;
}

Result:

Geostatic

Thanks. Looks like it solved my problem. One more question: is XSetBackground needed on Expose event handler? Everything works fine without this call, but may be it is needed in some purposes. – Vinificator

@Vinificator No. Oh damn it, sorry, that was a leftover from my experiment. Code fixed. – Geostatic

Is it possible to draw that rectangle with mouse as in the case of rubberbanding? – Supererogate

@Supererogate Sure, why not. The code would look quite a bit different though. – Geostatic

@Geostatic would you post a sample code please? Shall I ask it as a question? – Supererogate

@Supererogate For starters, please at least try doing it yourself. – Geostatic