1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
4
5 This software is provided 'as-is', without any express or implied
6 warranty. In no event will the authors be held liable for any damages
7 arising from the use of this software.
8
9 Permission is granted to anyone to use this software for any purpose,
10 including commercial applications, and to alter it and redistribute it
11 freely, subject to the following restrictions:
12
13 1. The origin of this software must not be misrepresented; you must not
14 claim that you wrote the original software. If you use this software
15 in a product, an acknowledgment in the product documentation would be
16 appreciated but is not required.
17 2. Altered source versions must be plainly marked as such, and must not be
18 misrepresented as being the original software.
19 3. This notice may not be removed or altered from any source distribution.
20*/
21#include "SDL_internal.h"
22
23#ifdef SDL_VIDEO_DRIVER_X11
24
25#include "SDL_x11video.h"
26#include "SDL_x11shape.h"
27
28
29#ifdef SDL_VIDEO_DRIVER_X11_XSHAPE
30static Uint8 *GenerateShapeMask(SDL_Surface *shape)
31{
32 int x, y;
33 const size_t ppb = 8;
34 const size_t bytes_per_scanline = (shape->w + (ppb - 1)) / ppb;
35 const Uint8 *a;
36 Uint8 *mask;
37 Uint8 *mask_scanline;
38 Uint8 mask_value;
39
40 mask = (Uint8 *)SDL_calloc(1, shape->h * bytes_per_scanline);
41 if (mask) {
42 for (y = 0; y < shape->h; y++) {
43 a = (const Uint8 *)shape->pixels + y * shape->pitch;
44 mask_scanline = mask + y * bytes_per_scanline;
45 for (x = 0; x < shape->w; x++) {
46 mask_value = (*a == SDL_ALPHA_TRANSPARENT) ? 0 : 1;
47 mask_scanline[x / ppb] |= mask_value << (x % ppb);
48 a += 4;
49 }
50 }
51 }
52 return mask;
53}
54#endif // SDL_VIDEO_DRIVER_X11_XSHAPE
55
56bool X11_UpdateWindowShape(SDL_VideoDevice *_this, SDL_Window *window, SDL_Surface *shape)
57{
58 bool result = false;
59
60#ifdef SDL_VIDEO_DRIVER_X11_XSHAPE
61 SDL_WindowData *windowdata = window->internal;
62
63 // Generate a set of spans for the region
64 if (shape) {
65 SDL_Surface *stretched = NULL;
66 Uint8 *mask;
67 Pixmap pixmap;
68
69 if (shape->w != window->w || shape->h != window->h) {
70 stretched = SDL_CreateSurface(window->w, window->h, SDL_PIXELFORMAT_ARGB32);
71 if (!stretched) {
72 return false;
73 }
74 if (!SDL_StretchSurface(shape, NULL, stretched, NULL, SDL_SCALEMODE_LINEAR)) {
75 SDL_DestroySurface(stretched);
76 return false;
77 }
78 shape = stretched;
79 }
80
81 mask = GenerateShapeMask(shape);
82 if (mask) {
83 pixmap = X11_XCreateBitmapFromData(windowdata->videodata->display, windowdata->xwindow, (const char *)mask, shape->w, shape->h);
84 X11_XShapeCombineMask(windowdata->videodata->display, windowdata->xwindow, ShapeInput, 0, 0, pixmap, ShapeSet);
85 SDL_free(mask);
86
87 result = true;
88 }
89
90 if (stretched) {
91 SDL_DestroySurface(stretched);
92 }
93 } else {
94 Region region = X11_XCreateRegion();
95 XRectangle rect;
96
97 rect.x = 0;
98 rect.y = 0;
99 rect.width = window->w;
100 rect.height = window->h;
101 X11_XUnionRectWithRegion(&rect, region, region);
102 X11_XShapeCombineRegion(windowdata->videodata->display, windowdata->xwindow, ShapeInput, 0, 0, region, ShapeSet);
103 X11_XDestroyRegion(region);
104 result = true;
105 }
106#endif // SDL_VIDEO_DRIVER_X11_XSHAPE
107
108 return result;
109}
110
111#endif // SDL_VIDEO_DRIVER_X11
112