SDL_rect.h File Reference

#include "SDL_stdinc.h"
#include "SDL_error.h"
#include "SDL_pixels.h"
#include "SDL_rwops.h"
#include "begin_code.h"
#include "close_code.h"

Include dependency graph for SDL_rect.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Data Structures
struct	SDL_Point
	The structure that defines a point. More...
struct	SDL_Rect
	A rectangle, with the origin at the upper left. More...

Functions
SDL_FORCE_INLINE SDL_bool	SDL_PointInRect (const SDL_Point *p, const SDL_Rect *r)
	Returns true if point resides inside a rectangle.
SDL_FORCE_INLINE SDL_bool	SDL_RectEmpty (const SDL_Rect *r)
	Returns true if the rectangle has no area.
SDL_FORCE_INLINE SDL_bool	SDL_RectEquals (const SDL_Rect *a, const SDL_Rect *b)
	Returns true if the two rectangles are equal.
SDL_bool	SDL_HasIntersection (const SDL_Rect *A, const SDL_Rect *B)
	Determine whether two rectangles intersect.
SDL_bool	SDL_IntersectRect (const SDL_Rect *A, const SDL_Rect *B, SDL_Rect *result)
	Calculate the intersection of two rectangles.
void	SDL_UnionRect (const SDL_Rect *A, const SDL_Rect *B, SDL_Rect *result)
	Calculate the union of two rectangles.
SDL_bool	SDL_EnclosePoints (const SDL_Point *points, int count, const SDL_Rect *clip, SDL_Rect *result)
	Calculate a minimal rectangle enclosing a set of points.
SDL_bool	SDL_IntersectRectAndLine (const SDL_Rect *rect, int *X1, int *Y1, int *X2, int *Y2)
	Calculate the intersection of a rectangle and line segment.

Detailed Description

Header file for SDL_rect definition and management functions.

Definition in file SDL_rect.h.

Function Documentation

SDL_bool SDL_EnclosePoints	(	const SDL_Point *	points,
		int	count,
		const SDL_Rect *	clip,
		SDL_Rect *	result
	)

Calculate a minimal rectangle enclosing a set of points.

Returns

SDL_TRUE if any points were within the clipping rect

Definition at line 192 of file SDL_rect.c.

References SDL_Rect::h, i, NULL, SDL_FALSE, SDL_InvalidParamError, SDL_RectEmpty(), SDL_TRUE, SDL_Rect::w, SDL_Point::x, SDL_Rect::x, SDL_Point::y, and SDL_Rect::y.

{
    int minx = 0;
    int miny = 0;
    int maxx = 0;
    int maxy = 0;
    int x, y, i;

    if (!points) {
        SDL_InvalidParamError("points");
        return SDL_FALSE;
    }

    if (count < 1) {
        SDL_InvalidParamError("count");
        return SDL_FALSE;
    }

    if (clip) {
        SDL_bool added = SDL_FALSE;
        const int clip_minx = clip->x;
        const int clip_miny = clip->y;
        const int clip_maxx = clip->x+clip->w-1;
        const int clip_maxy = clip->y+clip->h-1;

        /* Special case for empty rectangle */
        if (SDL_RectEmpty(clip)) {
            return SDL_FALSE;
        }

        for (i = 0; i < count; ++i) {
            x = points[i].x;
            y = points[i].y;

            if (x < clip_minx || x > clip_maxx ||
                y < clip_miny || y > clip_maxy) {
                continue;
            }
            if (!added) {
                /* Special case: if no result was requested, we are done */
                if (result == NULL) {
                    return SDL_TRUE;
                }

                /* First point added */
                minx = maxx = x;
                miny = maxy = y;
                added = SDL_TRUE;
                continue;
            }
            if (x < minx) {
                minx = x;
            } else if (x > maxx) {
                maxx = x;
            }
            if (y < miny) {
                miny = y;
            } else if (y > maxy) {
                maxy = y;
            }
        }
        if (!added) {
            return SDL_FALSE;
        }
    } else {
        /* Special case: if no result was requested, we are done */
        if (result == NULL) {
            return SDL_TRUE;
        }

        /* No clipping, always add the first point */
        minx = maxx = points[0].x;
        miny = maxy = points[0].y;

        for (i = 1; i < count; ++i) {
            x = points[i].x;
            y = points[i].y;

            if (x < minx) {
                minx = x;
            } else if (x > maxx) {
                maxx = x;
            }
            if (y < miny) {
                miny = y;
            } else if (y > maxy) {
                maxy = y;
            }
        }
    }

    if (result) {
        result->x = minx;
        result->y = miny;
        result->w = (maxx-minx)+1;
        result->h = (maxy-miny)+1;
    }
    return SDL_TRUE;
}

SDL_bool SDL_HasIntersection	(	const SDL_Rect *	A,
		const SDL_Rect *	B
	)

Determine whether two rectangles intersect.

Returns

SDL_TRUE if there is an intersection, SDL_FALSE otherwise.

Definition at line 28 of file SDL_rect.c.

References SDL_Rect::h, SDL_FALSE, SDL_InvalidParamError, SDL_RectEmpty(), SDL_TRUE, SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.

{
    int Amin, Amax, Bmin, Bmax;

    if (!A) {
        SDL_InvalidParamError("A");
        return SDL_FALSE;
    }

    if (!B) {
        SDL_InvalidParamError("B");
        return SDL_FALSE;
    }

    /* Special cases for empty rects */
    if (SDL_RectEmpty(A) || SDL_RectEmpty(B)) {
        return SDL_FALSE;
    }

    /* Horizontal intersection */
    Amin = A->x;
    Amax = Amin + A->w;
    Bmin = B->x;
    Bmax = Bmin + B->w;
    if (Bmin > Amin)
        Amin = Bmin;
    if (Bmax < Amax)
        Amax = Bmax;
    if (Amax <= Amin)
        return SDL_FALSE;

    /* Vertical intersection */
    Amin = A->y;
    Amax = Amin + A->h;
    Bmin = B->y;
    Bmax = Bmin + B->h;
    if (Bmin > Amin)
        Amin = Bmin;
    if (Bmax < Amax)
        Amax = Bmax;
    if (Amax <= Amin)
        return SDL_FALSE;

    return SDL_TRUE;
}

SDL_bool SDL_IntersectRect	(	const SDL_Rect *	A,
		const SDL_Rect *	B,
		SDL_Rect *	result
	)

Calculate the intersection of two rectangles.

Returns

SDL_TRUE if there is an intersection, SDL_FALSE otherwise.

Definition at line 75 of file SDL_rect.c.

References SDL_Rect::h, SDL_FALSE, SDL_InvalidParamError, SDL_RectEmpty(), SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.

{
    int Amin, Amax, Bmin, Bmax;

    if (!A) {
        SDL_InvalidParamError("A");
        return SDL_FALSE;
    }

    if (!B) {
        SDL_InvalidParamError("B");
        return SDL_FALSE;
    }

    if (!result) {
        SDL_InvalidParamError("result");
        return SDL_FALSE;
    }

    /* Special cases for empty rects */
    if (SDL_RectEmpty(A) || SDL_RectEmpty(B)) {
        result->w = 0;
        result->h = 0;
        return SDL_FALSE;
    }

    /* Horizontal intersection */
    Amin = A->x;
    Amax = Amin + A->w;
    Bmin = B->x;
    Bmax = Bmin + B->w;
    if (Bmin > Amin)
        Amin = Bmin;
    result->x = Amin;
    if (Bmax < Amax)
        Amax = Bmax;
    result->w = Amax - Amin;

    /* Vertical intersection */
    Amin = A->y;
    Amax = Amin + A->h;
    Bmin = B->y;
    Bmax = Bmin + B->h;
    if (Bmin > Amin)
        Amin = Bmin;
    result->y = Amin;
    if (Bmax < Amax)
        Amax = Bmax;
    result->h = Amax - Amin;

    return !SDL_RectEmpty(result);
}

SDL_bool SDL_IntersectRectAndLine	(	const SDL_Rect *	rect,
		int *	X1,
		int *	Y1,
		int *	X2,
		int *	Y2
	)

Calculate the intersection of a rectangle and line segment.

Returns

SDL_TRUE if there is an intersection, SDL_FALSE otherwise.

Definition at line 317 of file SDL_rect.c.

References CODE_BOTTOM, CODE_LEFT, CODE_RIGHT, CODE_TOP, ComputeOutCode(), SDL_Rect::h, SDL_assert, SDL_FALSE, SDL_InvalidParamError, SDL_RectEmpty(), SDL_TRUE, SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.

{
    int x = 0;
    int y = 0;
    int x1, y1;
    int x2, y2;
    int rectx1;
    int recty1;
    int rectx2;
    int recty2;
    int outcode1, outcode2;

    if (!rect) {
        SDL_InvalidParamError("rect");
        return SDL_FALSE;
    }

    if (!X1) {
        SDL_InvalidParamError("X1");
        return SDL_FALSE;
    }

    if (!Y1) {
        SDL_InvalidParamError("Y1");
        return SDL_FALSE;
    }

    if (!X2) {
        SDL_InvalidParamError("X2");
        return SDL_FALSE;
    }

    if (!Y2) {
        SDL_InvalidParamError("Y2");
        return SDL_FALSE;
    }

    /* Special case for empty rect */
    if (SDL_RectEmpty(rect)) {
        return SDL_FALSE;
    }

    x1 = *X1;
    y1 = *Y1;
    x2 = *X2;
    y2 = *Y2;
    rectx1 = rect->x;
    recty1 = rect->y;
    rectx2 = rect->x + rect->w - 1;
    recty2 = rect->y + rect->h - 1;

    /* Check to see if entire line is inside rect */
    if (x1 >= rectx1 && x1 <= rectx2 && x2 >= rectx1 && x2 <= rectx2 &&
        y1 >= recty1 && y1 <= recty2 && y2 >= recty1 && y2 <= recty2) {
        return SDL_TRUE;
    }

    /* Check to see if entire line is to one side of rect */
    if ((x1 < rectx1 && x2 < rectx1) || (x1 > rectx2 && x2 > rectx2) ||
        (y1 < recty1 && y2 < recty1) || (y1 > recty2 && y2 > recty2)) {
        return SDL_FALSE;
    }

    if (y1 == y2) {
        /* Horizontal line, easy to clip */
        if (x1 < rectx1) {
            *X1 = rectx1;
        } else if (x1 > rectx2) {
            *X1 = rectx2;
        }
        if (x2 < rectx1) {
            *X2 = rectx1;
        } else if (x2 > rectx2) {
            *X2 = rectx2;
        }
        return SDL_TRUE;
    }

    if (x1 == x2) {
        /* Vertical line, easy to clip */
        if (y1 < recty1) {
            *Y1 = recty1;
        } else if (y1 > recty2) {
            *Y1 = recty2;
        }
        if (y2 < recty1) {
            *Y2 = recty1;
        } else if (y2 > recty2) {
            *Y2 = recty2;
        }
        return SDL_TRUE;
    }

    /* More complicated Cohen-Sutherland algorithm */
    outcode1 = ComputeOutCode(rect, x1, y1);
    outcode2 = ComputeOutCode(rect, x2, y2);
    while (outcode1 || outcode2) {
        if (outcode1 & outcode2) {
            return SDL_FALSE;
        }

        if (outcode1) {
            if (outcode1 & CODE_TOP) {
                y = recty1;
                x = x1 + ((x2 - x1) * (y - y1)) / (y2 - y1);
            } else if (outcode1 & CODE_BOTTOM) {
                y = recty2;
                x = x1 + ((x2 - x1) * (y - y1)) / (y2 - y1);
            } else if (outcode1 & CODE_LEFT) {
                x = rectx1;
                y = y1 + ((y2 - y1) * (x - x1)) / (x2 - x1);
            } else if (outcode1 & CODE_RIGHT) {
                x = rectx2;
                y = y1 + ((y2 - y1) * (x - x1)) / (x2 - x1);
            }
            x1 = x;
            y1 = y;
            outcode1 = ComputeOutCode(rect, x, y);
        } else {
            if (outcode2 & CODE_TOP) {
                y = recty1;
                x = x1 + ((x2 - x1) * (y - y1)) / (y2 - y1);
            } else if (outcode2 & CODE_BOTTOM) {
                y = recty2;
                x = x1 + ((x2 - x1) * (y - y1)) / (y2 - y1);
            } else if (outcode2 & CODE_LEFT) {
                /* If this assertion ever fires, here's the static analysis that warned about it:
                   http://buildbot.libsdl.org/sdl-static-analysis/sdl-macosx-static-analysis/sdl-macosx-static-analysis-1101/report-b0d01a.html#EndPath */
                SDL_assert(x2 != x1);  /* if equal: division by zero. */
                x = rectx1;
                y = y1 + ((y2 - y1) * (x - x1)) / (x2 - x1);
            } else if (outcode2 & CODE_RIGHT) {
                /* If this assertion ever fires, here's the static analysis that warned about it:
                   http://buildbot.libsdl.org/sdl-static-analysis/sdl-macosx-static-analysis/sdl-macosx-static-analysis-1101/report-39b114.html#EndPath */
                SDL_assert(x2 != x1);  /* if equal: division by zero. */
                x = rectx2;
                y = y1 + ((y2 - y1) * (x - x1)) / (x2 - x1);
            }
            x2 = x;
            y2 = y;
            outcode2 = ComputeOutCode(rect, x, y);
        }
    }
    *X1 = x1;
    *Y1 = y1;
    *X2 = x2;
    *Y2 = y2;
    return SDL_TRUE;
}

SDL_FORCE_INLINE SDL_bool SDL_PointInRect	(	const SDL_Point *	p,
		const SDL_Rect *	r
	)

Returns true if point resides inside a rectangle.

Definition at line 73 of file SDL_rect.h.

References SDL_Rect::h, SDL_FALSE, SDL_TRUE, SDL_Rect::w, SDL_Point::x, SDL_Rect::x, SDL_Point::y, and SDL_Rect::y.

Referenced by hitTest().

{
    return ( (p->x >= r->x) && (p->x < (r->x + r->w)) &&
             (p->y >= r->y) && (p->y < (r->y + r->h)) ) ? SDL_TRUE : SDL_FALSE;
}

SDL_FORCE_INLINE SDL_bool SDL_RectEmpty

(

const SDL_Rect *

r

)

Returns true if the rectangle has no area.

Definition at line 82 of file SDL_rect.h.

References SDL_Rect::h, SDL_FALSE, SDL_TRUE, and SDL_Rect::w.

Referenced by rect_testIntersectRectEmpty(), rect_testRectEmpty(), rect_testRectEmptyParam(), SDL_EnclosePoints(), SDL_FillRect(), SDL_HasIntersection(), SDL_IntersectRect(), SDL_IntersectRectAndLine(), SDL_SoftBlit(), SDL_UnionRect(), and SDLTest_CommonEvent().

{
    return ((!r) || (r->w <= 0) || (r->h <= 0)) ? SDL_TRUE : SDL_FALSE;
}

SDL_FORCE_INLINE SDL_bool SDL_RectEquals	(	const SDL_Rect *	a,
		const SDL_Rect *	b
	)

Returns true if the two rectangles are equal.

Definition at line 90 of file SDL_rect.h.

References SDL_Rect::h, SDL_FALSE, SDL_TRUE, SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.

Referenced by rect_testRectEquals(), and rect_testRectEqualsParam().

{
    return (a && b && (a->x == b->x) && (a->y == b->y) &&
            (a->w == b->w) && (a->h == b->h)) ? SDL_TRUE : SDL_FALSE;
}

void SDL_UnionRect	(	const SDL_Rect *	A,
		const SDL_Rect *	B,
		SDL_Rect *	result
	)

Calculate the union of two rectangles.

Definition at line 129 of file SDL_rect.c.

References SDL_Rect::h, SDL_InvalidParamError, SDL_RectEmpty(), SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.

{
    int Amin, Amax, Bmin, Bmax;

    if (!A) {
        SDL_InvalidParamError("A");
        return;
    }

    if (!B) {
        SDL_InvalidParamError("B");
        return;
    }

    if (!result) {
        SDL_InvalidParamError("result");
        return;
    }

    /* Special cases for empty Rects */
    if (SDL_RectEmpty(A)) {
      if (SDL_RectEmpty(B)) {
       /* A and B empty */
       return;
      } else {
       /* A empty, B not empty */
       *result = *B;
       return;
      }
    } else {
      if (SDL_RectEmpty(B)) {
       /* A not empty, B empty */
       *result = *A;
       return;
      }
    }

    /* Horizontal union */
    Amin = A->x;
    Amax = Amin + A->w;
    Bmin = B->x;
    Bmax = Bmin + B->w;
    if (Bmin < Amin)
        Amin = Bmin;
    result->x = Amin;
    if (Bmax > Amax)
        Amax = Bmax;
    result->w = Amax - Amin;

    /* Vertical union */
    Amin = A->y;
    Amax = Amin + A->h;
    Bmin = B->y;
    Bmax = Bmin + B->h;
    if (Bmin < Amin)
        Amin = Bmin;
    result->y = Amin;
    if (Bmax > Amax)
        Amax = Bmax;
    result->h = Amax - Amin;
}