src/video/SDL_shape.c
author egottlieb
Sun, 15 Aug 2010 21:46:04 -0400
changeset 4852 c19c729eb201
parent 4851 5624fb0190b5
child 4855 6d4d6605a0d3
permissions -rw-r--r--
Added hiding-as-positioning trick and finally fixed flags.

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 2010 Eli Gottlieb

    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

    Eli Gottlieb
    eligottlieb@gmail.com
*/
#include "SDL_config.h"

#include "SDL.h"
#include "SDL_assert.h"
#include "SDL_video.h"
#include "SDL_sysvideo.h"
#include "SDL_pixels.h"
#include "SDL_surface.h"
#include "SDL_shape.h"
#include "SDL_shape_internals.h"

SDL_Window*
SDL_CreateShapedWindow(const char *title,unsigned int x,unsigned int y,unsigned int w,unsigned int h,Uint32 flags) {
    SDL_Window *result = SDL_CreateWindow(title,x,y,w,h,flags | SDL_WINDOW_BORDERLESS & ~SDL_WINDOW_FULLSCREEN & ~SDL_WINDOW_RESIZABLE);
    if(result != NULL) {
        result->shaper = result->display->device->shape_driver.CreateShaper(result);
        if(result->shaper != NULL) {
            result->shaper->userx = x;
            result->shaper->usery = y;
            result->shaper->mode.mode = ShapeModeDefault;
            result->shaper->mode.parameters.binarizationCutoff = 1;
            result->shaper->hasshape = SDL_FALSE;
            return result;
        }
        else {
            SDL_DestroyWindow(result);
            return NULL;
        }
    }
    else
        return NULL;
}

SDL_bool
SDL_IsShapedWindow(const SDL_Window *window) {
    if(window == NULL)
        return SDL_FALSE;
    else
        return (SDL_bool)(window->shaper != NULL);
}

/* REQUIRES that bitmap point to a w-by-h bitmap with ppb pixels-per-byte. */
void
SDL_CalculateShapeBitmap(SDL_WindowShapeMode mode,SDL_Surface *shape,Uint8* bitmap,Uint8 ppb) {
    int x = 0;
    int y = 0;
    Uint8 r = 0,g = 0,b = 0,alpha = 0;
    Uint8* pixel = NULL;
    Uint32 bitmap_pixel,pixel_value = 0,mask_value = 0;
    SDL_Color key;
    if(SDL_MUSTLOCK(shape))
        SDL_LockSurface(shape);
    pixel = (Uint8*)shape->pixels;
    for(y = 0;y<shape->h;y++) {
        for(x=0;x<shape->w;x++) {
            alpha = 0;
            pixel_value = 0;
            pixel = (Uint8 *)(shape->pixels) + (y*shape->pitch) + (x*shape->format->BytesPerPixel);
            switch(shape->format->BytesPerPixel) {
                case(1):
                    pixel_value = *(Uint8*)pixel;
                    break;
                case(2):
                    pixel_value = *(Uint16*)pixel;
                    break;
                case(3):
                    pixel_value = *(Uint32*)pixel & (~shape->format->Amask);
                    break;
                case(4):
                    pixel_value = *(Uint32*)pixel;
                    break;
            }
            SDL_GetRGBA(pixel_value,shape->format,&r,&g,&b,&alpha);
            bitmap_pixel = y*shape->w + x;
            switch(mode.mode) {
                case(ShapeModeDefault):
                    mask_value = (alpha >= 1 ? 1 : 0);
                    break;
                case(ShapeModeBinarizeAlpha):
                    mask_value = (alpha >= mode.parameters.binarizationCutoff ? 1 : 0);
                    break;
                case(ShapeModeReverseBinarizeAlpha):
                    mask_value = (alpha <= mode.parameters.binarizationCutoff ? 1 : 0);
                    break;
                case(ShapeModeColorKey):
                    key = mode.parameters.colorKey;
                    mask_value = ((key.r != r || key.g != g || key.b != b) ? 1 : 0);
                    break;
            }
            bitmap[bitmap_pixel / ppb] |= mask_value << (7 - ((ppb - 1) - (bitmap_pixel % ppb)));
        }
    }
    if(SDL_MUSTLOCK(shape))
        SDL_UnlockSurface(shape);
}

SDL_ShapeTree*
RecursivelyCalculateShapeTree(SDL_WindowShapeMode mode,SDL_Surface* mask,SDL_Rect dimensions) {
    int x = 0,y = 0;
    Uint8* pixel = NULL;
    Uint32 pixel_value = 0;
    Uint8 r = 0,g = 0,b = 0,a = 0;
    SDL_bool pixel_opaque = SDL_FALSE;
    int last_opaque = -1;
    SDL_Color key;
    SDL_ShapeTree* result = (SDL_ShapeTree*)SDL_malloc(sizeof(SDL_ShapeTree));
    SDL_Rect next = {0,0,0,0};
    for(y=dimensions.y;y<dimensions.y + dimensions.h;y++) {
        for(x=dimensions.x;x<dimensions.x + dimensions.w;x++) {
            pixel_value = 0;
            pixel = (Uint8 *)(mask->pixels) + (y*mask->pitch) + (x*mask->format->BytesPerPixel);
            switch(mask->format->BytesPerPixel) {
                case(1):
                    pixel_value = *(Uint8*)pixel;
                    break;
                case(2):
                    pixel_value = *(Uint16*)pixel;
                    break;
                case(3):
                    pixel_value = *(Uint32*)pixel & (~mask->format->Amask);
                    break;
                case(4):
                    pixel_value = *(Uint32*)pixel;
                    break;
            }
            SDL_GetRGBA(pixel_value,mask->format,&r,&g,&b,&a);
            switch(mode.mode) {
                case(ShapeModeDefault):
                    pixel_opaque = (a >= 1 ? SDL_TRUE : SDL_FALSE);
                    break;
                case(ShapeModeBinarizeAlpha):
                    pixel_opaque = (a >= mode.parameters.binarizationCutoff ? SDL_TRUE : SDL_FALSE);
                    break;
                case(ShapeModeReverseBinarizeAlpha):
                    pixel_opaque = (a <= mode.parameters.binarizationCutoff ? SDL_TRUE : SDL_FALSE);
                    break;
                case(ShapeModeColorKey):
                    key = mode.parameters.colorKey;
                    pixel_opaque = ((key.r != r || key.g != g || key.b != b) ? SDL_TRUE : SDL_FALSE);
                    break;
            }
            if(last_opaque == -1)
                last_opaque = pixel_opaque;
            if(last_opaque != pixel_opaque) {
                result->kind = QuadShape;
                //These will stay the same.
                next.w = dimensions.w / 2;
                next.h = dimensions.h / 2;
                //These will change from recursion to recursion.
                next.x = dimensions.x;
                next.y = dimensions.y;
                result->data.children.upleft = (struct SDL_ShapeTree *)RecursivelyCalculateShapeTree(mode,mask,next);
                next.x += next.w;
                //Unneeded: next.y = dimensions.y;
                result->data.children.upright = (struct SDL_ShapeTree *)RecursivelyCalculateShapeTree(mode,mask,next);
                next.x = dimensions.x;
                next.y += next.h;
                result->data.children.downleft = (struct SDL_ShapeTree *)RecursivelyCalculateShapeTree(mode,mask,next);
                next.x += next.w;
                //Unneeded: next.y = dimensions.y + dimensions.h /2;
                result->data.children.downright = (struct SDL_ShapeTree *)RecursivelyCalculateShapeTree(mode,mask,next);
                return result;
            }
        }
    }
    //If we never recursed, all the pixels in this quadrant have the same "value".
    result->kind = (last_opaque == SDL_TRUE ? OpaqueShape : TransparentShape);
    result->data.shape = dimensions;
    return result;
}

SDL_ShapeTree*
SDL_CalculateShapeTree(SDL_WindowShapeMode mode,SDL_Surface* shape) {
    SDL_Rect dimensions = {0,0,shape->w,shape->h};
    SDL_ShapeTree* result = NULL;
    if(SDL_MUSTLOCK(shape))
        SDL_LockSurface(shape);
    result = RecursivelyCalculateShapeTree(mode,shape,dimensions);
    if(SDL_MUSTLOCK(shape))
        SDL_UnlockSurface(shape);
    return result;
}

void
SDL_TraverseShapeTree(SDL_ShapeTree *tree,SDL_TraversalFunction function,void* closure) {
    SDL_assert(tree != NULL);
    if(tree->kind == QuadShape) {
        SDL_TraverseShapeTree((SDL_ShapeTree *)tree->data.children.upleft,function,closure);
        SDL_TraverseShapeTree((SDL_ShapeTree *)tree->data.children.upright,function,closure);
        SDL_TraverseShapeTree((SDL_ShapeTree *)tree->data.children.downleft,function,closure);
        SDL_TraverseShapeTree((SDL_ShapeTree *)tree->data.children.downright,function,closure);
    }
    else
        function(tree,closure);
}

void
SDL_FreeShapeTree(SDL_ShapeTree** shape_tree) {
    if((*shape_tree)->kind == QuadShape) {
        SDL_FreeShapeTree((SDL_ShapeTree **)&(*shape_tree)->data.children.upleft);
        SDL_FreeShapeTree((SDL_ShapeTree **)&(*shape_tree)->data.children.upright);
        SDL_FreeShapeTree((SDL_ShapeTree **)&(*shape_tree)->data.children.downleft);
        SDL_FreeShapeTree((SDL_ShapeTree **)&(*shape_tree)->data.children.downright);
    }
    SDL_free(*shape_tree);
    *shape_tree = NULL;
}

int
SDL_SetWindowShape(SDL_Window *window,SDL_Surface *shape,SDL_WindowShapeMode *shape_mode) {
    int result;
    if(window == NULL || !SDL_IsShapedWindow(window))
        //The window given was not a shapeable window.
        return SDL_NONSHAPEABLE_WINDOW;
    if(shape == NULL)
        //Invalid shape argument.
        return SDL_INVALID_SHAPE_ARGUMENT;
    
    if(shape_mode != NULL)
        window->shaper->mode = *shape_mode;
    result = window->display->device->shape_driver.SetWindowShape(window->shaper,shape,shape_mode);
    window->shaper->hasshape = SDL_TRUE;
    if(window->shaper->userx != 0 && window->shaper->usery != 0) {
        SDL_SetWindowPosition(window,window->shaper->userx,window->shaper->usery);
        window->shaper->userx = 0;
        window->shaper->usery = 0;
    }
    return result;
}

SDL_bool
SDL_WindowHasAShape(SDL_Window *window) {
    if (window == NULL || !SDL_IsShapedWindow(window))
        return SDL_FALSE;
    return window->shaper->hasshape;
}

int
SDL_GetShapedWindowMode(SDL_Window *window,SDL_WindowShapeMode *shape_mode) {
    if(window != NULL && SDL_IsShapedWindow(window)) {
        if(shape_mode == NULL) {
            if(SDL_WindowHasAShape(window))
                //The window given has a shape.
                return 0;
            else
                //The window given is shapeable but lacks a shape.
                return SDL_WINDOW_LACKS_SHAPE;
        }
        else {
            *shape_mode = window->shaper->mode;
            return 0;
        }
    }
    else
        //The window given is not a valid shapeable window.
        return SDL_NONSHAPEABLE_WINDOW;
}