src/events/SDL_mouse.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2010 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"
#include "../video/SDL_sysvideo.h"


/* Global mouse information */

typedef struct SDL_Mouse SDL_Mouse;

struct SDL_Mouse
{
    /* Create a cursor from a surface */
    SDL_Cursor *(*CreateCursor) (SDL_Surface * surface, int hot_x, int hot_y);

    /* Show the specified cursor, or hide if cursor is NULL */
    int (*ShowCursor) (SDL_Cursor * cursor);

    /* This is called when a mouse motion event occurs */
    void (*MoveCursor) (SDL_Cursor * cursor);

    /* Free a window manager cursor */
    void (*FreeCursor) (SDL_Cursor * cursor);

    /* Warp the mouse to (x,y) */
    void (*WarpMouse) (SDL_Mouse * mouse, SDL_Window * window, int x, int y);

    /* Data common to all mice */
    SDL_Window *focus;
    int x;
    int y;
    int xdelta;
    int ydelta;
    int last_x, last_y;         /* the last reported x and y coordinates */
    Uint8 buttonstate;
    SDL_bool relative_mode;

    SDL_Cursor *cursors;
    SDL_Cursor *def_cursor;
    SDL_Cursor *cur_cursor;
    SDL_bool cursor_shown;
};

static SDL_Mouse SDL_mouse;


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

void
SDL_ResetMouse(void)
{
    /* FIXME */
}

SDL_Window *
SDL_GetMouseFocus(void)
{
    SDL_Mouse *mouse = &SDL_mouse;

    return mouse->focus;
}

void
SDL_SetMouseFocus(SDL_Window * window)
{
    SDL_Mouse *mouse = &SDL_mouse;

    if (mouse->focus == window) {
        return;
    }

    /* See if the current window has lost focus */
    if (mouse->focus) {
        SDL_SendWindowEvent(mouse->focus, SDL_WINDOWEVENT_LEAVE, 0, 0);
    }

    mouse->focus = window;

    if (mouse->focus) {
        SDL_SendWindowEvent(mouse->focus, SDL_WINDOWEVENT_ENTER, 0, 0);
    }
}

int
SDL_SendMouseMotion(SDL_Window * window, int relative, int x, int y)
{
    SDL_Mouse *mouse = &SDL_mouse;
    int posted;
    int xrel;
    int yrel;
    int x_max = 0, y_max = 0;

    if (window) {
        SDL_SetMouseFocus(window);
    }

    /* the relative motion is calculated regarding the system cursor last position */
    if (relative) {
        xrel = x;
        yrel = y;
        x = (mouse->last_x + x);
        y = (mouse->last_y + y);
    } else {
        xrel = x - mouse->last_x;
        yrel = y - mouse->last_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 coordinates */
    if (mouse->relative_mode == SDL_FALSE) {
        mouse->x = x;
        mouse->y = y;
    } else {
        mouse->x += xrel;
        mouse->y += yrel;
    }

    SDL_GetWindowSize(mouse->focus, &x_max, &y_max);

    /* make sure that the pointers find themselves inside the windows */
    /* only check if mouse->xmax is set ! */
    if (x_max && mouse->x > x_max) {
        mouse->x = x_max;
    } else if (mouse->x < 0) {
        mouse->x = 0;
    }

    if (y_max && mouse->y > y_max) {
        mouse->y = y_max;
    } else if (mouse->y < 0) {
        mouse->y = 0;
    }

    mouse->xdelta += xrel;
    mouse->ydelta += yrel;

#if 0 /* FIXME */
    /* Move the mouse cursor, if needed */
    if (mouse->cursor_shown && !mouse->relative_mode &&
        mouse->MoveCursor && mouse->cur_cursor) {
        mouse->MoveCursor(mouse->cur_cursor);
    }
#endif

    /* Post the event, if desired */
    posted = 0;
    if (SDL_GetEventState(SDL_MOUSEMOTION) == SDL_ENABLE) {
        SDL_Event event;
        event.motion.type = SDL_MOUSEMOTION;
        event.motion.windowID = mouse->focus ? mouse->focus->id : 0;
        event.motion.state = mouse->buttonstate;
        event.motion.x = mouse->x;
        event.motion.y = mouse->y;
        event.motion.xrel = xrel;
        event.motion.yrel = yrel;
        posted = (SDL_PushEvent(&event) > 0);
    }
    mouse->last_x = mouse->x;
    mouse->last_y = mouse->y;
    return posted;
}

int
SDL_SendMouseButton(SDL_Window * window, Uint8 state, Uint8 button)
{
    SDL_Mouse *mouse = &SDL_mouse;
    int posted;
    Uint32 type;

    if (window) {
        SDL_SetMouseFocus(window);
    }

    /* 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_GetEventState(type) == SDL_ENABLE) {
        SDL_Event event;
        event.type = type;
        event.button.state = state;
        event.button.button = button;
        event.button.x = mouse->x;
        event.button.y = mouse->y;
        event.button.windowID = mouse->focus ? mouse->focus->id : 0;
        posted = (SDL_PushEvent(&event) > 0);
    }
    return posted;
}

int
SDL_SendMouseWheel(SDL_Window * window, int x, int y)
{
    SDL_Mouse *mouse = &SDL_mouse;
    int posted;

    if (window) {
        SDL_SetMouseFocus(window);
    }

    if (!x && !y) {
        return 0;
    }

    /* Post the event, if desired */
    posted = 0;
    if (SDL_GetEventState(SDL_MOUSEWHEEL) == SDL_ENABLE) {
        SDL_Event event;
        event.type = SDL_MOUSEWHEEL;
        event.wheel.windowID = mouse->focus ? mouse->focus->id : 0;
        event.wheel.x = x;
        event.wheel.y = y;
        posted = (SDL_PushEvent(&event) > 0);
    }
    return posted;
}

void
SDL_MouseQuit(void)
{
}

Uint8
SDL_GetMouseState(int *x, int *y)
{
    SDL_Mouse *mouse = &SDL_mouse;

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

Uint8
SDL_GetRelativeMouseState(int *x, int *y)
{
    SDL_Mouse *mouse = &SDL_mouse;

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

void
SDL_WarpMouseInWindow(SDL_Window * window, int x, int y)
{
    SDL_Mouse *mouse = &SDL_mouse;

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

int
SDL_SetRelativeMouseMode(SDL_bool enabled)
{
    SDL_Mouse *mouse = &SDL_mouse;

    /* Flush pending mouse motion */
    SDL_FlushEvent(SDL_MOUSEMOTION);

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

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

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

    return 0;
}

SDL_bool
SDL_GetRelativeMouseMode()
{
    SDL_Mouse *mouse = &SDL_mouse;

    return mouse->relative_mode;
}

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

    if (!mouse->CreateCursor) {
        SDL_SetError("Cursors are not currently supported");
        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->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_mouse;

    /* 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_mouse;

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

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

    if (!cursor) {
        return;
    }

    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_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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