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factored out blitting constraints check in a seperate function

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the checking of the boundaries when blitting was incomplete
for the addblitToBuffer() function when compared with the
blitToBuffer() function. Factored out the redundant checking
procedure into a new function.

Should fix another bug leading to issue #401 and probably
more cases for specifying boundary boxes.
This commit is contained in:
HW
2012-10-10 17:58:31 +02:00
committed by Qingping Hou
parent cf38d02e80
commit 4b2a9237c9
1 changed files with 63 additions and 71 deletions
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134
blitbuffer.c
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@@ -105,6 +105,63 @@ static int blitFullToBuffer(lua_State *L) {
return 0;
}
/**
* check/adapt boundaries for blitting operations
*
* @return 0 if no blitting is needed, 1 otherwise
*/
int fitBlitBufferBoundaries(BlitBuffer* src, BlitBuffer* dst, int* xdest, int* ydest, int* xoffs, int* yoffs, int* w, int* h) {
// check bounds
if(*ydest < 0) {
// negative ydest, try to compensate
if(*ydest + *h > 0) {
// shrink h by negative dest offset
*h += *ydest;
// extend source offset
*yoffs += -(*ydest);
*ydest = 0;
} else {
// effectively no height
return 0;
}
} else if(*ydest >= dst->h) {
// we're told to paint to off-bound target coords
return 0;
}
if(*ydest + *h > dst->h) {
// clamp height if too large for target size
*h = dst->h - *ydest;
}
if(*yoffs >= src->h) {
// recalculated source offset is out of bounds
return 0;
} else if(*yoffs + *h > src->h) {
// clamp height if too large for source size
*h = src->h - *yoffs;
}
// same stuff for x coords:
if(*xdest < 0) {
if(*xdest + *w > 0) {
*w += *xdest;
*xoffs += -(*xdest);
*xdest = 0;
} else {
return 0;
}
} else if(*xdest >= dst->w) {
return 0;
}
if(*xdest + *w > dst->w) {
*w = dst->w - *xdest;
}
if(*xoffs >= src->w) {
return 0;
} else if(*xoffs + *w > src->w) {
*w = src->w - *xoffs;
}
return 1; // continue processing
}
static int blitToBuffer(lua_State *L) {
BlitBuffer *dst = (BlitBuffer*) luaL_checkudata(L, 1, "blitbuffer");
BlitBuffer *src = (BlitBuffer*) luaL_checkudata(L, 2, "blitbuffer");
@@ -116,58 +173,12 @@ static int blitToBuffer(lua_State *L) {
int h = luaL_checkint(L, 8);
int x, y;
// check bounds
if(ydest < 0) {
// negative ydest, try to compensate
if(ydest + h > 0) {
// shrink h by negative dest offset
h += ydest;
// extend source offset
yoffs += -ydest;
ydest = 0;
} else {
// effectively no height
return 0;
}
} else if(ydest >= dst->h) {
// we're told to paint to off-bound target coords
return 0;
}
if(ydest + h > dst->h) {
// clamp height if too large for target size
h = dst->h - ydest;
}
if(yoffs >= src->h) {
// recalculated source offset is out of bounds
return 0;
} else if(yoffs + h > src->h) {
// clamp height if too large for source size
h = src->h - yoffs;
}
// same stuff for x coords:
if(xdest < 0) {
if(xdest + w > 0) {
w += xdest;
xoffs += -xdest;
xdest = 0;
} else {
return 0;
}
} else if(xdest >= dst->w) {
return 0;
}
if(xdest + w > dst->w) {
w = dst->w - xdest;
}
if(xoffs >= src->w) {
return 0;
} else if(xoffs + w > src->w) {
w = src->w - xoffs;
}
uint8_t *dstptr;
uint8_t *srcptr;
if(!fitBlitBufferBoundaries(src, dst, &xdest, &ydest, &xoffs, &yoffs, &w, &h))
return 0;
if(xdest & 1) {
/* this will render the leftmost column */
dstptr = (uint8_t*)(dst->data +
@@ -248,31 +259,12 @@ static int addblitToBuffer(lua_State *L) {
int h = luaL_checkint(L, 8);
int x, y;
// check bounds
if(yoffs >= src->h) {
return 0;
} else if(yoffs + h > src->h) {
h = src->h - yoffs;
}
if(ydest >= dst->h) {
return 0;
} else if(ydest + h > dst->h) {
h = dst->h - ydest;
}
if(xoffs >= src->w) {
return 0;
} else if(xoffs + w > src->w) {
w = src->w - xoffs;
}
if(xdest >= dst->w) {
return 0;
} else if(xdest + w > dst->w) {
w = dst->w - xdest;
}
uint8_t *dstptr;
uint8_t *srcptr;
if(!fitBlitBufferBoundaries(src, dst, &xdest, &ydest, &xoffs, &yoffs, &w, &h))
return 0;
if(xdest & 1) {
/* this will render the leftmost column */
dstptr = (uint8_t*)(dst->data +