Source code of Windows XP (NT5)
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/******************************Module*Header*******************************\
* Module Name: Strips.c
*
* These are the line rendering routines of last resort, and are called
* by 'bLines' when a line is clipped or otherwise cannot be drawn
* directly by the hardware.
*
* Copyright (c) 1992-1995 Microsoft Corporation
\**************************************************************************/
#include "precomp.h"
/******************************Public*Routine******************************\
* VOID vStripSolidHorizontal
*
* Draws left-to-right x-major near-horizontal lines using radial lines.
*
\**************************************************************************/
VOID vStripSolidHorizontal(
PDEV* ppdev,
STRIP* pStrip,
LINESTATE* pLineState)
{
BYTE* pjBase;
LONG x;
LONG y;
LONG yDir;
LONG* pStrips;
LONG cStrips;
LONG i;
pjBase = ppdev->pjBase;
x = pStrip->ptlStart.x;
y = pStrip->ptlStart.y;
yDir = (pStrip->flFlips & FL_FLIP_V) ? -1 : 1;
pStrips = pStrip->alStrips;
cStrips = pStrip->cStrips;
for (i = cStrips; i != 0; i--)
{
CP_METALINE(ppdev, pjBase, x, y);
x += *pStrips++;
CP_METALINE(ppdev, pjBase, x - 1, y);
y += yDir;
CP_START_QUAD_WAIT(ppdev, pjBase);
}
pStrip->ptlStart.x = x;
pStrip->ptlStart.y = y;
}
/******************************Public*Routine******************************\
* VOID vStripSolidVertical
*
* Draws left-to-right y-major near-vertical lines using radial lines.
*
\**************************************************************************/
VOID vStripSolidVertical(
PDEV* ppdev,
STRIP* pStrip,
LINESTATE* pLineState)
{
BYTE* pjBase;
LONG x;
LONG y;
LONG yDir;
LONG* pStrips;
LONG cStrips;
LONG i;
pjBase = ppdev->pjBase;
x = pStrip->ptlStart.x;
y = pStrip->ptlStart.y;
yDir = (pStrip->flFlips & FL_FLIP_V) ? -1 : 1;
pStrips = pStrip->alStrips;
cStrips = pStrip->cStrips;
for (i = cStrips; i != 0; i--)
{
CP_METALINE(ppdev, pjBase, x, y);
y += (yDir > 0) ? *pStrips : -*pStrips;
pStrips++;
CP_METALINE(ppdev, pjBase, x, y - yDir);
x++;
CP_START_QUAD_WAIT(ppdev, pjBase);
}
pStrip->ptlStart.x = x;
pStrip->ptlStart.y = y;
}
/******************************Public*Routine******************************\
* VOID vStripSolidDiagonalHorizontal
*
* Draws left-to-right x-major near-diagonal lines using radial lines.
*
\**************************************************************************/
VOID vStripSolidDiagonalHorizontal(
PDEV* ppdev,
STRIP* pStrip,
LINESTATE* pLineState)
{
BYTE* pjBase;
LONG x;
LONG y;
LONG yDir;
LONG* pStrips;
LONG cStrips;
LONG i;
pjBase = ppdev->pjBase;
x = pStrip->ptlStart.x;
y = pStrip->ptlStart.y;
yDir = (pStrip->flFlips & FL_FLIP_V) ? -1 : 1;
pStrips = pStrip->alStrips;
cStrips = pStrip->cStrips;
for (i = cStrips; i != 0; i--)
{
CP_METALINE(ppdev, pjBase, x, y);
x += *pStrips;
y += (yDir > 0) ? *pStrips : -*pStrips;
pStrips++;
CP_METALINE(ppdev, pjBase, x - 1, y - yDir);
y -= yDir;
CP_START_QUAD_WAIT(ppdev, pjBase);
}
pStrip->ptlStart.x = x;
pStrip->ptlStart.y = y;
}
/******************************Public*Routine******************************\
* VOID vStripSolidDiagonalVertical
*
* Draws left-to-right y-major near-diagonal lines using radial lines.
*
\**************************************************************************/
VOID vStripSolidDiagonalVertical(
PDEV* ppdev,
STRIP* pStrip,
LINESTATE* pLineState)
{
BYTE* pjBase;
LONG x;
LONG y;
LONG yDir;
LONG* pStrips;
LONG cStrips;
LONG i;
pjBase = ppdev->pjBase;
x = pStrip->ptlStart.x;
y = pStrip->ptlStart.y;
yDir = (pStrip->flFlips & FL_FLIP_V) ? -1 : 1;
pStrips = pStrip->alStrips;
cStrips = pStrip->cStrips;
for (i = cStrips; i != 0; i--)
{
CP_METALINE(ppdev, pjBase, x, y);
x += *pStrips;
y += (yDir > 0) ? *pStrips : -*pStrips;
pStrips++;
CP_METALINE(ppdev, pjBase, x - 1, y - yDir);
x--;
CP_START_QUAD_WAIT(ppdev, pjBase);
}
pStrip->ptlStart.x = x;
pStrip->ptlStart.y = y;
}
/******************************Public*Routine******************************\
* VOID vStripStyledHorizontal
*
* Takes the list of strips that define the pixels that would be lit for
* a solid line, and breaks them into styling chunks according to the
* styling information that is passed in.
*
* This particular routine handles x-major lines that run left-to-right,
* and are comprised of horizontal strips. It draws the dashes using
* short-stroke vectors.
*
* The performance of this routine could be improved significantly if
* anyone cared enough about styled lines improve it.
*
\**************************************************************************/
VOID vStripStyledHorizontal(
PDEV* ppdev,
STRIP* pstrip,
LINESTATE* pls)
{
BYTE* pjBase;
LONG x;
LONG y;
LONG dy;
LONG* plStrip;
LONG cStrips;
LONG cStyle;
LONG cStrip;
LONG cThis;
ULONG bIsGap;
pjBase = ppdev->pjBase;
if (pstrip->flFlips & FL_FLIP_V)
{
// The minor direction of the line is 90 degrees, and the major
// direction is 0 (it's a left-to-right x-major line going up):
dy = -1;
}
else
{
// The minor direction of the line is 270 degrees, and the major
// direction is 0 (it's a left-to-right x-major line going down):
dy = 1;
}
cStrips = pstrip->cStrips; // Total number of strips we'll do
plStrip = pstrip->alStrips; // Points to current strip
x = pstrip->ptlStart.x; // x position of start of first strip
y = pstrip->ptlStart.y; // y position of start of first strip
cStrip = *plStrip; // Number of pels in first strip
cStyle = pls->spRemaining; // Number of pels in first 'gap' or 'dash'
bIsGap = pls->ulStyleMask; // Tells whether in a 'gap' or a 'dash'
// ulStyleMask is non-zero if we're in the middle of a 'gap',
// and zero if we're in the middle of a 'dash':
if (bIsGap)
goto SkipAGap;
else
goto OutputADash;
PrepareToSkipAGap:
// Advance in the style-state array, so that we can find the next
// 'dot' that we'll have to display:
bIsGap = ~bIsGap;
pls->psp++;
if (pls->psp > pls->pspEnd)
pls->psp = pls->pspStart;
cStyle = *pls->psp;
// If 'cStrip' is zero, we also need a new strip:
if (cStrip != 0)
goto SkipAGap;
// Here, we're in the middle of a 'gap' where we don't have to
// display anything. We simply cycle through all the strips
// we can, keeping track of the current position, until we run
// out of 'gap':
while (TRUE)
{
// Each time we loop, we move to a new scan and need a new strip:
y += dy;
plStrip++;
cStrips--;
if (cStrips == 0)
goto AllDone;
cStrip = *plStrip;
SkipAGap:
cThis = min(cStrip, cStyle);
cStyle -= cThis;
cStrip -= cThis;
x += cThis;
if (cStyle == 0)
goto PrepareToOutputADash;
}
PrepareToOutputADash:
// Advance in the style-state array, so that we can find the next
// 'dot' that we'll have to display:
bIsGap = ~bIsGap;
pls->psp++;
if (pls->psp > pls->pspEnd)
pls->psp = pls->pspStart;
cStyle = *pls->psp;
// If 'cStrip' is zero, we also need a new strip.
if (cStrip != 0)
{
// There's more to be done in the current strip:
goto OutputADash;
}
// We've finished with the current strip:
while (TRUE)
{
// Each time we loop, we move to a new scan and need a new strip:
y += dy;
plStrip++;
cStrips--;
if (cStrips == 0)
goto AllDone;
cStrip = *plStrip;
OutputADash:
cThis = min(cStrip, cStyle);
cStyle -= cThis;
cStrip -= cThis;
// Short stroke vectors can handle lines that are a maximum of
// 15 pels long. When we have to draw a longer consecutive
// segment than that, we simply break it into 16 pel portions:
CP_METALINE(ppdev, pjBase, x, y);
x += cThis;
CP_METALINE(ppdev, pjBase, x - 1, y);
CP_START_QUAD_WAIT(ppdev, pjBase);
if (cStyle == 0)
goto PrepareToSkipAGap;
}
AllDone:
// Update our state variables so that the next line can continue
// where we left off:
pls->spRemaining = cStyle;
pls->ulStyleMask = bIsGap;
pstrip->ptlStart.x = x;
pstrip->ptlStart.y = y;
}
/******************************Public*Routine******************************\
* VOID vStripStyledVertical
*
* Takes the list of strips that define the pixels that would be lit for
* a solid line, and breaks them into styling chunks according to the
* styling information that is passed in.
*
* This particular routine handles y-major lines that run left-to-right,
* and are comprised of vertical strips. It draws the dashes using
* short-stroke vectors.
*
* The performance of this routine could be improved significantly if
* anyone cared enough about styled lines improve it.
*
\**************************************************************************/
VOID vStripStyledVertical(
PDEV* ppdev,
STRIP* pstrip,
LINESTATE* pls)
{
BYTE* pjBase;
LONG x;
LONG y;
LONG dy;
LONG* plStrip;
LONG cStrips;
LONG cStyle;
LONG cStrip;
LONG cThis;
ULONG bIsGap;
pjBase = ppdev->pjBase;
if (pstrip->flFlips & FL_FLIP_V)
{
// The minor direction of the line is 0 degrees, and the major
// direction is 90 (it's a left-to-right y-major line going up):
dy = -1;
}
else
{
// The minor direction of the line is 0 degrees, and the major
// direction is 270 (it's a left-to-right y-major line going down):
dy = 1;
}
cStrips = pstrip->cStrips; // Total number of strips we'll do
plStrip = pstrip->alStrips; // Points to current strip
x = pstrip->ptlStart.x; // x position of start of first strip
y = pstrip->ptlStart.y; // y position of start of first strip
cStrip = *plStrip; // Number of pels in first strip
cStyle = pls->spRemaining; // Number of pels in first 'gap' or 'dash'
bIsGap = pls->ulStyleMask; // Tells whether in a 'gap' or a 'dash'
// ulStyleMask is non-zero if we're in the middle of a 'gap',
// and zero if we're in the middle of a 'dash':
if (bIsGap)
goto SkipAGap;
else
goto OutputADash;
PrepareToSkipAGap:
// Advance in the style-state array, so that we can find the next
// 'dot' that we'll have to display:
bIsGap = ~bIsGap;
pls->psp++;
if (pls->psp > pls->pspEnd)
pls->psp = pls->pspStart;
cStyle = *pls->psp;
// If 'cStrip' is zero, we also need a new strip:
if (cStrip != 0)
goto SkipAGap;
// Here, we're in the middle of a 'gap' where we don't have to
// display anything. We simply cycle through all the strips
// we can, keeping track of the current position, until we run
// out of 'gap':
while (TRUE)
{
// Each time we loop, we move to a new column and need a new strip:
x++;
plStrip++;
cStrips--;
if (cStrips == 0)
goto AllDone;
cStrip = *plStrip;
SkipAGap:
cThis = min(cStrip, cStyle);
cStyle -= cThis;
cStrip -= cThis;
y += (dy > 0) ? cThis : -cThis;
if (cStyle == 0)
goto PrepareToOutputADash;
}
PrepareToOutputADash:
// Advance in the style-state array, so that we can find the next
// 'dot' that we'll have to display:
bIsGap = ~bIsGap;
pls->psp++;
if (pls->psp > pls->pspEnd)
pls->psp = pls->pspStart;
cStyle = *pls->psp;
// If 'cStrip' is zero, we also need a new strip.
if (cStrip != 0)
{
// There's more to be done in the current strip:
goto OutputADash;
}
// We've finished with the current strip:
while (TRUE)
{
// Each time we loop, we move to a new column and need a new strip:
x++;
plStrip++;
cStrips--;
if (cStrips == 0)
goto AllDone;
cStrip = *plStrip;
OutputADash:
cThis = min(cStrip, cStyle);
cStyle -= cThis;
cStrip -= cThis;
CP_METALINE(ppdev, pjBase, x, y);
y += (dy > 0) ? cThis : -cThis;
CP_METALINE(ppdev, pjBase, x, y - dy);
CP_START_QUAD_WAIT(ppdev, pjBase);
if (cStyle == 0)
goto PrepareToSkipAGap;
}
AllDone:
// Update our state variables so that the next line can continue
// where we left off:
pls->spRemaining = cStyle;
pls->ulStyleMask = bIsGap;
pstrip->ptlStart.x = x;
pstrip->ptlStart.y = y;
}