src/video/x11/SDL_x11mouse.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2011 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"
#include "SDL_x11video.h"
#include "SDL_x11mouse.h"
#include "../../events/SDL_mouse_c.h"


/* FIXME: Find a better place to put this... */
static Cursor x11_empty_cursor = None;

static Display *
GetDisplay(void)
{
    return ((SDL_VideoData *)SDL_GetVideoDevice()->driverdata)->display;
}

static Cursor
X11_CreateEmptyCursor()
{
    if (x11_empty_cursor == None) {
        Display *display = GetDisplay();
        char data[1];
        XColor color;
        Pixmap pixmap;

        SDL_zero(data);
        color.red = color.green = color.blue = 0;
        pixmap = XCreateBitmapFromData(display, DefaultRootWindow(display),
                                       data, 1, 1);
        if (pixmap) {
            x11_empty_cursor = XCreatePixmapCursor(display, pixmap, pixmap,
                                                   &color, &color, 0, 0);
            XFreePixmap(display, pixmap);
        }
    }
    return x11_empty_cursor;
}

static void
X11_DestroyEmptyCursor(void)
{
    if (x11_empty_cursor != None) {
        XFreeCursor(GetDisplay(), x11_empty_cursor);
        x11_empty_cursor = None;
    }
}

static SDL_Cursor *
X11_CreateDefaultCursor()
{
    SDL_Cursor *cursor;

    cursor = SDL_calloc(1, sizeof(*cursor));
    if (cursor) {
        /* None is used to indicate the default cursor */
        cursor->driverdata = (void*)None;
    } else {
        SDL_OutOfMemory();
    }

    return cursor;
}

static Cursor
X11_CreatePixmapCursor(SDL_Surface * surface, int hot_x, int hot_y)
{
    Display *display = GetDisplay();
    XColor fg, bg;
    Cursor cursor = None;
    Uint32 *ptr;
    Uint8 *data_bits, *mask_bits;
    Pixmap data_pixmap, mask_pixmap;
    int x, y;
    unsigned int rfg, gfg, bfg, rbg, gbg, bbg, fgBits, bgBits;
    unsigned int width_bytes = ((surface->w + 7) & ~7) / 8;

    data_bits = SDL_calloc(1, surface->h * width_bytes);
    mask_bits = SDL_calloc(1, surface->h * width_bytes);
    if (!data_bits || !mask_bits) {
        SDL_OutOfMemory();
        return None;
    }

    rfg = gfg = bfg = rbg = gbg = bbg = fgBits = 0;
    for (y = 0; y < surface->h; ++y) {
        ptr = (Uint32 *)((Uint8 *)surface->pixels + y * surface->pitch);
        for (x = 0; x < surface->w; ++x) {
            int alpha = (*ptr >> 24) & 0xff;
            int red   = (*ptr >> 16) & 0xff;
            int green = (*ptr >> 8) & 0xff;
            int blue  = (*ptr >> 0) & 0xff;
            if (alpha > 25) {
                mask_bits[y * width_bytes + x / 8] |= (0x01 << (x % 8));

                if ((red + green + blue) > 0x40) {
                    fgBits++;
                    rfg += red;
                    gfg += green;
                    bfg += blue;
                    data_bits[y * width_bytes + x / 8] |= (0x01 << (x % 8));
                } else {
                    bgBits++;
                    rbg += red;
                    gbg += green;
                    bbg += blue;
                }
            }
            ++ptr;
        }
    }

    if (fgBits) {
        fg.red   = rfg * 257 / fgBits;
        fg.green = gfg * 257 / fgBits;
        fg.blue  = bfg * 257 / fgBits;
    }
    else fg.red = fg.green = fg.blue = 0;

    if (bgBits) {
        bg.red   = rbg * 257 / bgBits;
        bg.green = gbg * 257 / bgBits;
        bg.blue  = bbg * 257 / bgBits;
    }
    else bg.red = bg.green = bg.blue = 0;

    data_pixmap = XCreateBitmapFromData(display, DefaultRootWindow(display),
                                        data_bits, surface->w, surface->h);
    mask_pixmap = XCreateBitmapFromData(display, DefaultRootWindow(display),
                                        mask_bits, surface->w, surface->h);
    cursor = XCreatePixmapCursor(display, data_pixmap, mask_pixmap,
                                 &fg, &bg, hot_x, hot_y);
	XFreePixmap(display, data_pixmap);
	XFreePixmap(display, mask_pixmap);

    return cursor;
}

static SDL_Cursor *
X11_CreateCursor(SDL_Surface * surface, int hot_x, int hot_y)
{
    SDL_Cursor *cursor;

    cursor = SDL_calloc(1, sizeof(*cursor));
    if (cursor) {
        cursor->driverdata = (void*)X11_CreatePixmapCursor(surface, hot_x, hot_y);
    } else {
        SDL_OutOfMemory();
    }

    return cursor;
}

static void
X11_FreeCursor(SDL_Cursor * cursor)
{
    Cursor x11_cursor = (Cursor)cursor->driverdata;

    if (x11_cursor != None) {
        XFreeCursor(GetDisplay(), x11_cursor);
    }
    SDL_free(cursor);
}

static int
X11_ShowCursor(SDL_Cursor * cursor)
{
    Cursor x11_cursor = 0;

    if (cursor) {
        x11_cursor = (Cursor)cursor->driverdata;
    } else {
        x11_cursor = X11_CreateEmptyCursor();
    }

    /* FIXME: Is there a better way than this? */
    {
        SDL_VideoDevice *video = SDL_GetVideoDevice();
        Display *display = GetDisplay();
        SDL_Window *window;
        SDL_WindowData *data;

        for (window = video->windows; window; window = window->next) {
            data = (SDL_WindowData *)window->driverdata;
            if (x11_cursor != None) {
                XDefineCursor(display, data->xwindow, x11_cursor);
            } else {
                XUndefineCursor(display, data->xwindow);
            }
        }
        XFlush(display);
    }
    return 0;
}

static void
X11_WarpMouse(SDL_Window * window, int x, int y)
{
    SDL_WindowData *data = (SDL_WindowData *) window->driverdata;
    Display *display = data->videodata->display;

    XWarpPointer(display, None, data->xwindow, 0, 0, 0, 0, x, y);
    XSync(display, False);
}

static int
X11_SetRelativeMouseMode(SDL_bool enabled)
{
    SDL_Unsupported();
    return -1;
}

void
X11_InitMouse(_THIS)
{
    SDL_Mouse *mouse = SDL_GetMouse();

    mouse->CreateCursor = X11_CreateCursor;
    mouse->ShowCursor = X11_ShowCursor;
    mouse->FreeCursor = X11_FreeCursor;
    mouse->WarpMouse = X11_WarpMouse;
    mouse->SetRelativeMouseMode = X11_SetRelativeMouseMode;

    SDL_SetDefaultCursor(X11_CreateDefaultCursor());
}

void
X11_QuitMouse(_THIS)
{
    X11_DestroyEmptyCursor();
}

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