Category : Files from Magazines
Archive : MAR93.ZIP
Filename : RGNOBJ.ASC
Output of file : RGNOBJ.ASC contained in archive : MAR93.ZIP
edited by Andrew Schulman
[LISTING ONE]
WORD GetGDIsegment(void)
{
HRGN (FAR PASCAL * A)(int, int, int, int);
unsigned short far * B;
WORD GDIseg; /* GDI segment */
A = CreateRectRgn;
B = (unsigned short far *)A; /* function prolog: MOV AX,DGROUP */
((char far *) B)++;
GDIseg = *B;
return GDIseg;
}
[LISTING TWO]
#include
WORD GetGDISegment(void)
{
SYSHEAPINFO info;
info.dwSize = sizeof(info);
SystemHeapInfo(&info);
return info.hGDISegment;
}
[LISTING THREE]
#include
static unsigned short far * ConvertRegionToAddress(HRGN region)
{
WORD GDIseg;
unsigned short far * * p; /* pointer to GDI segment */
unsigned short far * pv; /* pointer to region data */
GDIseg = GetGDIsegment();
FP_SEG(p) = GDIseg;
FP_OFF(p) = handle;
pv = (unsigned short far *) *p;
FP_SEG(pv) = GDIseg;
return pv;
}
[LISTING FOUR]
static tFixed ToFixed(int value)
{
return ((tFixed) value) << 16;
}
[LISTING FIVE]
static tFixed tFixMul(tFixed num1, tFixed num2)
{
tFixed result;
int negated = false;
unsigned short int2;
unsigned short frac2;
/* 'negated' is the sign of the result. We in effect store
the sign bits. This will fail if we give it -32768.0000 */
num1 = ((long) num1 < 0) ? negated = !negated, -num1 : num1;
num2 = ((long) num2 < 0) ? negated = !negated, -num2 : num2;
/* Extract the highword (integer part) and lowword (fraction
part) of the second operand */
int2 = (unsigned long) num2 >> 16;
frac2 = (unsigned long) num2 & 0xFFFF;
result=(((unsigned long) num1*frac2) >> 16)+((unsigned long) num1*int2);
return (negated ? -result : result);
}
[LISTING SIX]
static tFixed tFixRatio(int num, int denom)
{
tFixed result;
result = ((long) num << 16) / (long) denom;
return result;
}
[LISTING SEVEN]
static short tFixRound(tFixed num)
{
int negated = ((long) num < 0);
short result = negated ? (-num) >> 16 : num >> 16;
unsigned short low = negated ? (-num) & 0xFFFF : num & 0xFFFF;
if (negated)
return -result - (low > 0x7FFF ? 1 : 0);
else
return result + (low > 0x7FFF ? 1 : 0);
}
[LISTING EIGHT]
HRGN outer = CreateRectRgn(100,200,300,400);
HRGN inner = CreateRectRgn(110,210,290,390);
HRGN hollow = CreateRectRgn(0,0,0,0);
CombineRgn(hollow, outer, NULL, RGN_COPY);
CombineRgn(hollow, hollow, inner, RGN_DIFF);
[LISTING NINE]
static short MapScalar(short value, short srcOffset, short dstOffset,
tFixed scale)
{
return tFixRound(tFixMul(scale, ToFixed(value-srcOffset))) + dstOffset;
}
void MapRgn(HRGN rgn, RECT * srcRect, RECT * dstRect)
{
register short srcX = srcRect->left;
register short srcY = srcRect->top;
register short dstX = dstRect->left;
register short dstY = dstRect->top;
/* Compute the X-scale and Y-scale as the ratio of the
length of the source and destination width and height */
tFixed scaleX = tFixRatio( (dstRect->right - dstX),
(srcRect->right - srcX));
tFixed scaleY = tFixRatio( (dstRect->bottom - dstY),
(srcRect->bottom - srcY));
short ySpans; // number of Y-spans in the region
short yspan; // current Y-span being processed
short xSpans; // number of X-spans in this Y-span
short xspan; // current X-span being processed
short RgnLength; // length of region, in words
short * regionbase; // base of region data
short * scanC; // current region word
regionbase = ConvertRegionToAddress(rgn); // Point to beginning of region
scanC = regionbase; // start at base of region
scanC += 5; // skip GDI header, point to region length
if (GetSystemMetrics(SM_DEBUG) && (GetVersion() != 3))
scanC += 2; // adjust for 3.1+ Debug version!!
RgnLength = *scanC++; // word 5: region length
ySpans = *scanC++; // word 6: number of Y-spans
scanC += 1; // Skip to bounding box.
// Map bounding box for the region
*scanC++ = MapScalar(*scanC, srcX, dstX, scaleX); // left
*scanC++ = MapScalar(*scanC, srcY, dstY, scaleY); // top
*scanC++ = MapScalar(*scanC, srcX, dstX, scaleX); // right
*scanC++ = MapScalar(*scanC, srcY, dstY, scaleY); // bottom
for (yspan = 0; yspan < ySpans; yspan++)
{ /* foreach y-span */
xSpans = *scanC++ / 2;
// Now we are pointing to the y start and y end points. Scale them.
*scanC = MapScalar(*scanC, srcY, dstY, scaleY); // startY
scanC++;
*scanC = MapScalar(*scanC, srcY, dstY, scaleY); // endY
scanC++;
// We are pointing to the x limit pairs for this y-span.
// Iterate down these, scaling each of them
for (xspan = 0; xspan < xSpans; xspan++)
{ /* foreach x-span */
// now we are pointing to the x start and end points. Scale them
*scanC = MapScalar(*scanC, srcX, dstX, scaleX); // startX
scanC++;
*scanC = MapScalar(*scanC, srcX, dstX, scaleX); // endX
scanC++;
} /* foreach x-span */
// The next word is the second copy of the number of X spans * 2.
// Ignore it.
scanC++;
} /* foreach y-span */
}
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This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.
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