src/events/SDL_mouse.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 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"

/* General mouse handling code for SDL */

#include "SDL_events.h"
#include "SDL_events_c.h"
#include "default_cursor.h"


static int SDL_num_mice;
static int SDL_current_mouse;
static SDL_Mouse **SDL_mice;


/* Public functions */
int
SDL_MouseInit(void)
{
    return (0);
}

SDL_Mouse *
SDL_GetMouse(int index)
{
    if (index < 0 || index >= SDL_num_mice) {
        return NULL;
    }
    return SDL_mice[index];
}

int
SDL_AddMouse(const SDL_Mouse * mouse, int index)
{
    SDL_Mouse **mice;
    int selected_mouse;

    /* Add the mouse to the list of mice */
    if (index < 0 || index >= SDL_num_mice || SDL_mice[index]) {
        mice =
            (SDL_Mouse **) SDL_realloc(SDL_mice,
                                       (SDL_num_mice + 1) * sizeof(*mice));
        if (!mice) {
            SDL_OutOfMemory();
            return -1;
        }

        SDL_mice = mice;
        index = SDL_num_mice++;
    }
    SDL_mice[index] = (SDL_Mouse *) SDL_malloc(sizeof(*SDL_mice[index]));
    if (!SDL_mice[index]) {
        SDL_OutOfMemory();
        return -1;
    }
    *SDL_mice[index] = *mouse;

    /* Create the default cursor for the mouse */
    SDL_mice[index]->cursor_shown = SDL_TRUE;
    selected_mouse = SDL_SelectMouse(index);
    SDL_mice[index]->cur_cursor = NULL;
    SDL_mice[index]->def_cursor =
        SDL_CreateCursor(default_cdata, default_cmask, DEFAULT_CWIDTH,
                         DEFAULT_CHEIGHT, DEFAULT_CHOTX, DEFAULT_CHOTY);
    SDL_SetCursor(SDL_mice[index]->def_cursor);
    SDL_SelectMouse(selected_mouse);

    return index;
}

void
SDL_DelMouse(int index)
{
    SDL_Mouse *mouse = SDL_GetMouse(index);

    if (!mouse) {
        return;
    }

    mouse->def_cursor = NULL;
    while (mouse->cursors) {
        SDL_FreeCursor(mouse->cursors);
    }

    if (mouse->FreeMouse) {
        mouse->FreeMouse(mouse);
    }
    SDL_free(mouse);

    SDL_mice[index] = NULL;
}

void
SDL_ResetMouse(int index)
{
    SDL_Mouse *mouse = SDL_GetMouse(index);

    if (!mouse) {
        return;
    }

    /* FIXME */
}

void
SDL_MouseQuit(void)
{
    int i;

    for (i = 0; i < SDL_num_mice; ++i) {
        SDL_DelMouse(i);
    }
    SDL_num_mice = 0;
    SDL_current_mouse = 0;

    if (SDL_mice) {
        SDL_free(SDL_mice);
        SDL_mice = NULL;
    }
}

int
SDL_GetNumMice(void)
{
    return SDL_num_mice;
}

int
SDL_SelectMouse(int index)
{
    if (index >= 0 && index < SDL_num_mice) {
        SDL_current_mouse = index;
    }
    return SDL_current_mouse;
}

SDL_WindowID
SDL_GetMouseFocusWindow()
{
    SDL_Mouse *mouse = SDL_GetMouse(SDL_current_mouse);

    if (!mouse) {
        return 0;
    }
    return mouse->focus;
}

static int
FlushMouseMotion(void *param, SDL_Event * event)
{
    if (event->type == SDL_MOUSEMOTION
        && event->motion.which == (Uint8) SDL_current_mouse) {
        return 0;
    } else {
        return 1;
    }
}

int
SDL_SetRelativeMouseMode(SDL_bool enabled)
{
    SDL_Mouse *mouse = SDL_GetMouse(SDL_current_mouse);

    if (!mouse) {
        return -1;
    }

    /* Flush pending mouse motion */
    mouse->flush_motion = SDL_TRUE;
    SDL_PumpEvents();
    mouse->flush_motion = SDL_FALSE;
    SDL_FilterEvents(FlushMouseMotion, mouse);

    /* Set the relative mode */
    mouse->relative_mode = enabled;

    /* Update cursor visibility */
    SDL_SetCursor(NULL);

    if (!enabled) {
        /* Restore the expected mouse position */
        SDL_WarpMouseInWindow(mouse->focus, mouse->x, mouse->y);
    }
    return 0;
}

SDL_bool
SDL_GetRelativeMouseMode()
{
    SDL_Mouse *mouse = SDL_GetMouse(SDL_current_mouse);

    if (!mouse) {
        return SDL_FALSE;
    }
    return mouse->relative_mode;
}

Uint8
SDL_GetMouseState(int *x, int *y)
{
    SDL_Mouse *mouse = SDL_GetMouse(SDL_current_mouse);

    if (!mouse) {
        if (x) {
            *x = 0;
        }
        if (y) {
            *y = 0;
        }
        return 0;
    }

    if (x) {
        *x = mouse->x;
    }
    if (y) {
        *y = mouse->y;
    }
    return mouse->buttonstate;
}

Uint8
SDL_GetRelativeMouseState(int *x, int *y)
{
    SDL_Mouse *mouse = SDL_GetMouse(SDL_current_mouse);

    if (!mouse) {
        if (x) {
            *x = 0;
        }
        if (y) {
            *y = 0;
        }
        return 0;
    }

    if (x) {
        *x = mouse->xdelta;
    }
    if (y) {
        *y = mouse->ydelta;
    }
    mouse->xdelta = 0;
    mouse->ydelta = 0;
    return mouse->buttonstate;
}

void
SDL_SetMouseFocus(int index, SDL_WindowID windowID)
{
    SDL_Mouse *mouse = SDL_GetMouse(index);
    int i;
    SDL_bool focus;

    if (!mouse || (mouse->focus == windowID)) {
        return;
    }

    /* See if the current window has lost focus */
    if (mouse->focus) {
        focus = SDL_FALSE;
        for (i = 0; i < SDL_num_mice; ++i) {
            SDL_Mouse *check;
            if (i != index) {
                check = SDL_GetMouse(i);
                if (check && check->focus == mouse->focus) {
                    focus = SDL_TRUE;
                    break;
                }
            }
        }
        if (!focus) {
            SDL_SendWindowEvent(mouse->focus, SDL_WINDOWEVENT_LEAVE, 0, 0);
        }
    }

    mouse->focus = windowID;

    if (mouse->focus) {
        focus = SDL_FALSE;
        for (i = 0; i < SDL_num_mice; ++i) {
            SDL_Mouse *check;
            if (i != index) {
                check = SDL_GetMouse(i);
                if (check && check->focus == mouse->focus) {
                    focus = SDL_TRUE;
                    break;
                }
            }
        }
        if (!focus) {
            SDL_SendWindowEvent(mouse->focus, SDL_WINDOWEVENT_ENTER, 0, 0);
        }
    }
}

int
SDL_SendMouseMotion(int index, int relative, int x, int y)
{
    SDL_Mouse *mouse = SDL_GetMouse(index);
    int posted;
    int xrel;
    int yrel;

    if (!mouse || mouse->flush_motion) {
        return 0;
    }

    if (relative) {
        /* Push the cursor around */
        xrel = x;
        yrel = y;
        x = (mouse->x + xrel);
        y = (mouse->y + yrel);
    } else {
        xrel = x - mouse->x;
        yrel = y - mouse->y;
    }

    /* Drop events that don't change state */
    if (!xrel && !yrel) {
#if 0
        printf("Mouse event didn't change state - dropped!\n");
#endif
        return 0;
    }

    /* Update internal mouse state */
    if (!mouse->relative_mode) {
        mouse->x = x;
        mouse->y = y;
    }
    mouse->xdelta += xrel;
    mouse->ydelta += yrel;

    /* Move the mouse cursor, if needed */
    if (mouse->cursor_shown && !mouse->relative_mode &&
        mouse->MoveCursor && mouse->cur_cursor) {
        mouse->MoveCursor(mouse->cur_cursor);
    }

    /* Post the event, if desired */
    posted = 0;
    if (SDL_ProcessEvents[SDL_MOUSEMOTION] == SDL_ENABLE) {
        SDL_Event event;
        event.motion.type = SDL_MOUSEMOTION;
        event.motion.which = (Uint8) index;
        event.motion.state = mouse->buttonstate;
        event.motion.x = mouse->x;
        event.motion.y = mouse->y;
        event.motion.xrel = xrel;
        event.motion.yrel = yrel;
        event.motion.windowID = mouse->focus;
        posted = (SDL_PushEvent(&event) > 0);
    }
    return posted;
}

int
SDL_SendMouseButton(int index, Uint8 state, Uint8 button)
{
    SDL_Mouse *mouse = SDL_GetMouse(index);
    int posted;
    Uint8 type;

    if (!mouse) {
        return 0;
    }

    /* Figure out which event to perform */
    switch (state) {
    case SDL_PRESSED:
        if (mouse->buttonstate & SDL_BUTTON(button)) {
            /* Ignore this event, no state change */
            return 0;
        }
        type = SDL_MOUSEBUTTONDOWN;
        mouse->buttonstate |= SDL_BUTTON(button);
        break;
    case SDL_RELEASED:
        if (!(mouse->buttonstate & SDL_BUTTON(button))) {
            /* Ignore this event, no state change */
            return 0;
        }
        type = SDL_MOUSEBUTTONUP;
        mouse->buttonstate &= ~SDL_BUTTON(button);
        break;
    default:
        /* Invalid state -- bail */
        return 0;
    }

    /* Post the event, if desired */
    posted = 0;
    if (SDL_ProcessEvents[type] == SDL_ENABLE) {
        SDL_Event event;
        event.type = type;
        event.button.which = (Uint8) index;
        event.button.state = state;
        event.button.button = button;
        event.button.x = mouse->x;
        event.button.y = mouse->y;
        event.button.windowID = mouse->focus;
        posted = (SDL_PushEvent(&event) > 0);
    }
    return posted;
}

int
SDL_SendMouseWheel(int index, int motion)
{
    SDL_Mouse *mouse = SDL_GetMouse(index);
    int posted;

    if (!mouse || !motion) {
        return 0;
    }

    /* Post the event, if desired */
    posted = 0;
    if (SDL_ProcessEvents[SDL_MOUSEWHEEL] == SDL_ENABLE) {
        SDL_Event event;
        event.type = SDL_MOUSEWHEEL;
        event.wheel.which = (Uint8) index;
        event.wheel.motion = motion;
        event.wheel.windowID = mouse->focus;
        posted = (SDL_PushEvent(&event) > 0);
    }
    return posted;
}

void
SDL_WarpMouseInWindow(SDL_WindowID windowID, int x, int y)
{
    SDL_Mouse *mouse = SDL_GetMouse(SDL_current_mouse);

    if (!mouse) {
        return;
    }

    if (mouse->WarpMouse) {
        mouse->WarpMouse(mouse, windowID, x, y);
    } else {
        SDL_SetMouseFocus(SDL_current_mouse, windowID);
        SDL_SendMouseMotion(SDL_current_mouse, 0, x, y);
    }
}

SDL_Cursor *
SDL_CreateCursor(const Uint8 * data, const Uint8 * mask,
                 int w, int h, int hot_x, int hot_y)
{
    SDL_Mouse *mouse = SDL_GetMouse(SDL_current_mouse);
    SDL_Surface *surface;
    SDL_Cursor *cursor;
    int x, y;
    Uint32 *pixel;
    Uint8 datab, maskb;
    const Uint32 black = 0xFF000000;
    const Uint32 white = 0xFFFFFFFF;
    const Uint32 transparent = 0x00000000;

    if (!mouse) {
        SDL_SetError("No mice are initialized");
        return NULL;
    }

    if (!mouse->CreateCursor) {
        SDL_SetError("Current mouse doesn't have cursor support");
        return NULL;
    }

    /* Sanity check the hot spot */
    if ((hot_x < 0) || (hot_y < 0) || (hot_x >= w) || (hot_y >= h)) {
        SDL_SetError("Cursor hot spot doesn't lie within cursor");
        return NULL;
    }

    /* Make sure the width is a multiple of 8 */
    w = ((w + 7) & ~7);

    /* Create the surface from a bitmap */
    surface =
        SDL_CreateRGBSurface(0, w, h, 32, 0x00FF0000, 0x0000FF00, 0x000000FF,
                             0xFF000000);
    if (!surface) {
        return NULL;
    }
    for (y = 0; y < h; ++y) {
        pixel = (Uint32 *) ((Uint8 *) surface->pixels + y * surface->pitch);
        for (x = 0; x < w; ++x) {
            if ((x % 8) == 0) {
                datab = *data++;
                maskb = *mask++;
            }
            if (maskb & 0x80) {
                *pixel++ = (datab & 0x80) ? black : white;
            } else {
                *pixel++ = (datab & 0x80) ? black : transparent;
            }
            datab <<= 1;
            maskb <<= 1;
        }
    }

    cursor = mouse->CreateCursor(surface, hot_x, hot_y);
    if (cursor) {
        cursor->mouse = mouse;
        cursor->next = mouse->cursors;
        mouse->cursors = cursor;
    }

    SDL_FreeSurface(surface);

    return cursor;
}

/* SDL_SetCursor(NULL) can be used to force the cursor redraw,
   if this is desired for any reason.  This is used when setting
   the video mode and when the SDL window gains the mouse focus.
 */
void
SDL_SetCursor(SDL_Cursor * cursor)
{
    SDL_Mouse *mouse = SDL_GetMouse(SDL_current_mouse);

    if (!mouse) {
        SDL_SetError("No mice are initialized");
        return;
    }

    /* Set the new cursor */
    if (cursor) {
        /* Make sure the cursor is still valid for this mouse */
        SDL_Cursor *found;
        for (found = mouse->cursors; found; found = found->next) {
            if (found == cursor) {
                break;
            }
        }
        if (!found) {
            SDL_SetError("Cursor not associated with the current mouse");
            return;
        }
        mouse->cur_cursor = cursor;
    } else {
        cursor = mouse->cur_cursor;
    }

    if (cursor && mouse->cursor_shown && !mouse->relative_mode) {
        if (mouse->ShowCursor) {
            mouse->ShowCursor(cursor);
        }
    } else {
        if (mouse->ShowCursor) {
            mouse->ShowCursor(NULL);
        }
    }
}

SDL_Cursor *
SDL_GetCursor(void)
{
    SDL_Mouse *mouse = SDL_GetMouse(SDL_current_mouse);

    if (!mouse) {
        return NULL;
    }
    return mouse->cur_cursor;
}

void
SDL_FreeCursor(SDL_Cursor * cursor)
{
    SDL_Mouse *mouse;
    SDL_Cursor *curr, *prev;

    if (!cursor) {
        return;
    }
    mouse = cursor->mouse;

    if (cursor == mouse->def_cursor) {
        return;
    }
    if (cursor == mouse->cur_cursor) {
        SDL_SetCursor(mouse->def_cursor);
    }

    for (prev = NULL, curr = mouse->cursors; curr;
         prev = curr, curr = curr->next) {
        if (curr == cursor) {
            if (prev) {
                prev->next = curr->next;
            } else {
                mouse->cursors = curr->next;
            }

            if (mouse->FreeCursor) {
                mouse->FreeCursor(curr);
            }
            return;
        }
    }
}

int
SDL_ShowCursor(int toggle)
{
    SDL_Mouse *mouse = SDL_GetMouse(SDL_current_mouse);
    SDL_bool shown;

    if (!mouse) {
        return 0;
    }

    shown = mouse->cursor_shown;
    if (toggle >= 0) {
        if (toggle) {
            mouse->cursor_shown = SDL_TRUE;
        } else {
            mouse->cursor_shown = SDL_FALSE;
        }
        if (mouse->cursor_shown != shown) {
            SDL_SetCursor(NULL);
        }
    }
    return shown;
}

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