+++ /dev/null
-/***********************************************************
-
-Copyright (c) 1987 X Consortium
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
-AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
-CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-Except as contained in this notice, the name of the X Consortium shall not be
-used in advertising or otherwise to promote the sale, use or other dealings
-in this Software without prior written authorization from the X Consortium.
-
-
-Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.
-
- All Rights Reserved
-
-Permission to use, copy, modify, and distribute this software and its
-documentation for any purpose and without fee is hereby granted,
-provided that the above copyright notice appear in all copies and that
-both that copyright notice and this permission notice appear in
-supporting documentation, and that the name of Digital not be
-used in advertising or publicity pertaining to distribution of the
-software without specific, written prior permission.
-
-DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
-ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
-DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
-ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
-WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
-ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
-SOFTWARE.
-
-******************************************************************/
-/* $XConsortium: mizerline.c,v 5.9 94/08/02 15:01:29 dpw Exp $ */
-#include "X.h"
-
-#include "misc.h"
-#include "scrnintstr.h"
-#include "gcstruct.h"
-#include "windowstr.h"
-#include "pixmap.h"
-#include "mi.h"
-#include "miline.h"
-
-/*
-
-The bresenham error equation used in the mi/mfb/cfb line routines is:
-
- e = error
- dx = difference in raw X coordinates
- dy = difference in raw Y coordinates
- M = # of steps in X direction
- N = # of steps in Y direction
- B = 0 to prefer diagonal steps in a given octant,
- 1 to prefer axial steps in a given octant
-
- For X major lines:
- e = 2Mdy - 2Ndx - dx - B
- -2dx <= e < 0
-
- For Y major lines:
- e = 2Ndx - 2Mdy - dy - B
- -2dy <= e < 0
-
-At the start of the line, we have taken 0 X steps and 0 Y steps,
-so M = 0 and N = 0:
-
- X major e = 2Mdy - 2Ndx - dx - B
- = -dx - B
-
- Y major e = 2Ndx - 2Mdy - dy - B
- = -dy - B
-
-At the end of the line, we have taken dx X steps and dy Y steps,
-so M = dx and N = dy:
-
- X major e = 2Mdy - 2Ndx - dx - B
- = 2dxdy - 2dydx - dx - B
- = -dx - B
- Y major e = 2Ndx - 2Mdy - dy - B
- = 2dydx - 2dxdy - dy - B
- = -dy - B
-
-Thus, the error term is the same at the start and end of the line.
-
-Let us consider clipping an X coordinate. There are 4 cases which
-represent the two independent cases of clipping the start vs. the
-end of the line and an X major vs. a Y major line. In any of these
-cases, we know the number of X steps (M) and we wish to find the
-number of Y steps (N). Thus, we will solve our error term equation.
-If we are clipping the start of the line, we will find the smallest
-N that satisfies our error term inequality. If we are clipping the
-end of the line, we will find the largest number of Y steps that
-satisfies the inequality. In that case, since we are representing
-the Y steps as (dy - N), we will actually want to solve for the
-smallest N in that equation.
-\f
-Case 1: X major, starting X coordinate moved by M steps
-
- -2dx <= 2Mdy - 2Ndx - dx - B < 0
- 2Ndx <= 2Mdy - dx - B + 2dx 2Ndx > 2Mdy - dx - B
- 2Ndx <= 2Mdy + dx - B N > (2Mdy - dx - B) / 2dx
- N <= (2Mdy + dx - B) / 2dx
-
-Since we are trying to find the smallest N that satisfies these
-equations, we should use the > inequality to find the smallest:
-
- N = floor((2Mdy - dx - B) / 2dx) + 1
- = floor((2Mdy - dx - B + 2dx) / 2dx)
- = floor((2Mdy + dx - B) / 2dx)
-
-Case 1b: X major, ending X coordinate moved to M steps
-
-Same derivations as Case 1, but we want the largest N that satisfies
-the equations, so we use the <= inequality:
-
- N = floor((2Mdy + dx - B) / 2dx)
-
-Case 2: X major, ending X coordinate moved by M steps
-
- -2dx <= 2(dx - M)dy - 2(dy - N)dx - dx - B < 0
- -2dx <= 2dxdy - 2Mdy - 2dxdy + 2Ndx - dx - B < 0
- -2dx <= 2Ndx - 2Mdy - dx - B < 0
- 2Ndx >= 2Mdy + dx + B - 2dx 2Ndx < 2Mdy + dx + B
- 2Ndx >= 2Mdy - dx + B N < (2Mdy + dx + B) / 2dx
- N >= (2Mdy - dx + B) / 2dx
-
-Since we are trying to find the highest number of Y steps that
-satisfies these equations, we need to find the smallest N, so
-we should use the >= inequality to find the smallest:
-
- N = ceiling((2Mdy - dx + B) / 2dx)
- = floor((2Mdy - dx + B + 2dx - 1) / 2dx)
- = floor((2Mdy + dx + B - 1) / 2dx)
-
-Case 2b: X major, starting X coordinate moved to M steps from end
-
-Same derivations as Case 2, but we want the smallest number of Y
-steps, so we want the highest N, so we use the < inequality:
-
- N = ceiling((2Mdy + dx + B) / 2dx) - 1
- = floor((2Mdy + dx + B + 2dx - 1) / 2dx) - 1
- = floor((2Mdy + dx + B + 2dx - 1 - 2dx) / 2dx)
- = floor((2Mdy + dx + B - 1) / 2dx)
-\f
-Case 3: Y major, starting X coordinate moved by M steps
-
- -2dy <= 2Ndx - 2Mdy - dy - B < 0
- 2Ndx >= 2Mdy + dy + B - 2dy 2Ndx < 2Mdy + dy + B
- 2Ndx >= 2Mdy - dy + B N < (2Mdy + dy + B) / 2dx
- N >= (2Mdy - dy + B) / 2dx
-
-Since we are trying to find the smallest N that satisfies these
-equations, we should use the >= inequality to find the smallest:
-
- N = ceiling((2Mdy - dy + B) / 2dx)
- = floor((2Mdy - dy + B + 2dx - 1) / 2dx)
- = floor((2Mdy - dy + B - 1) / 2dx) + 1
-
-Case 3b: Y major, ending X coordinate moved to M steps
-
-Same derivations as Case 3, but we want the largest N that satisfies
-the equations, so we use the < inequality:
-
- N = ceiling((2Mdy + dy + B) / 2dx) - 1
- = floor((2Mdy + dy + B + 2dx - 1) / 2dx) - 1
- = floor((2Mdy + dy + B + 2dx - 1 - 2dx) / 2dx)
- = floor((2Mdy + dy + B - 1) / 2dx)
-
-Case 4: Y major, ending X coordinate moved by M steps
-
- -2dy <= 2(dy - N)dx - 2(dx - M)dy - dy - B < 0
- -2dy <= 2dxdy - 2Ndx - 2dxdy + 2Mdy - dy - B < 0
- -2dy <= 2Mdy - 2Ndx - dy - B < 0
- 2Ndx <= 2Mdy - dy - B + 2dy 2Ndx > 2Mdy - dy - B
- 2Ndx <= 2Mdy + dy - B N > (2Mdy - dy - B) / 2dx
- N <= (2Mdy + dy - B) / 2dx
-
-Since we are trying to find the highest number of Y steps that
-satisfies these equations, we need to find the smallest N, so
-we should use the > inequality to find the smallest:
-
- N = floor((2Mdy - dy - B) / 2dx) + 1
-
-Case 4b: Y major, starting X coordinate moved to M steps from end
-
-Same analysis as Case 4, but we want the smallest number of Y steps
-which means the largest N, so we use the <= inequality:
-
- N = floor((2Mdy + dy - B) / 2dx)
-\f
-Now let's try the Y coordinates, we have the same 4 cases.
-
-Case 5: X major, starting Y coordinate moved by N steps
-
- -2dx <= 2Mdy - 2Ndx - dx - B < 0
- 2Mdy >= 2Ndx + dx + B - 2dx 2Mdy < 2Ndx + dx + B
- 2Mdy >= 2Ndx - dx + B M < (2Ndx + dx + B) / 2dy
- M >= (2Ndx - dx + B) / 2dy
-
-Since we are trying to find the smallest M, we use the >= inequality:
-
- M = ceiling((2Ndx - dx + B) / 2dy)
- = floor((2Ndx - dx + B + 2dy - 1) / 2dy)
- = floor((2Ndx - dx + B - 1) / 2dy) + 1
-
-Case 5b: X major, ending Y coordinate moved to N steps
-
-Same derivations as Case 5, but we want the largest M that satisfies
-the equations, so we use the < inequality:
-
- M = ceiling((2Ndx + dx + B) / 2dy) - 1
- = floor((2Ndx + dx + B + 2dy - 1) / 2dy) - 1
- = floor((2Ndx + dx + B + 2dy - 1 - 2dy) / 2dy)
- = floor((2Ndx + dx + B - 1) / 2dy)
-
-Case 6: X major, ending Y coordinate moved by N steps
-
- -2dx <= 2(dx - M)dy - 2(dy - N)dx - dx - B < 0
- -2dx <= 2dxdy - 2Mdy - 2dxdy + 2Ndx - dx - B < 0
- -2dx <= 2Ndx - 2Mdy - dx - B < 0
- 2Mdy <= 2Ndx - dx - B + 2dx 2Mdy > 2Ndx - dx - B
- 2Mdy <= 2Ndx + dx - B M > (2Ndx - dx - B) / 2dy
- M <= (2Ndx + dx - B) / 2dy
-
-Largest # of X steps means smallest M, so use the > inequality:
-
- M = floor((2Ndx - dx - B) / 2dy) + 1
-
-Case 6b: X major, starting Y coordinate moved to N steps from end
-
-Same derivations as Case 6, but we want the smallest # of X steps
-which means the largest M, so use the <= inequality:
-
- M = floor((2Ndx + dx - B) / 2dy)
-\f
-Case 7: Y major, starting Y coordinate moved by N steps
-
- -2dy <= 2Ndx - 2Mdy - dy - B < 0
- 2Mdy <= 2Ndx - dy - B + 2dy 2Mdy > 2Ndx - dy - B
- 2Mdy <= 2Ndx + dy - B M > (2Ndx - dy - B) / 2dy
- M <= (2Ndx + dy - B) / 2dy
-
-To find the smallest M, use the > inequality:
-
- M = floor((2Ndx - dy - B) / 2dy) + 1
- = floor((2Ndx - dy - B + 2dy) / 2dy)
- = floor((2Ndx + dy - B) / 2dy)
-
-Case 7b: Y major, ending Y coordinate moved to N steps
-
-Same derivations as Case 7, but we want the largest M that satisfies
-the equations, so use the <= inequality:
-
- M = floor((2Ndx + dy - B) / 2dy)
-
-Case 8: Y major, ending Y coordinate moved by N steps
-
- -2dy <= 2(dy - N)dx - 2(dx - M)dy - dy - B < 0
- -2dy <= 2dxdy - 2Ndx - 2dxdy + 2Mdy - dy - B < 0
- -2dy <= 2Mdy - 2Ndx - dy - B < 0
- 2Mdy >= 2Ndx + dy + B - 2dy 2Mdy < 2Ndx + dy + B
- 2Mdy >= 2Ndx - dy + B M < (2Ndx + dy + B) / 2dy
- M >= (2Ndx - dy + B) / 2dy
-
-To find the highest X steps, find the smallest M, use the >= inequality:
-
- M = ceiling((2Ndx - dy + B) / 2dy)
- = floor((2Ndx - dy + B + 2dy - 1) / 2dy)
- = floor((2Ndx + dy + B - 1) / 2dy)
-
-Case 8b: Y major, starting Y coordinate moved to N steps from the end
-
-Same derivations as Case 8, but we want to find the smallest # of X
-steps which means the largest M, so we use the < inequality:
-
- M = ceiling((2Ndx + dy + B) / 2dy) - 1
- = floor((2Ndx + dy + B + 2dy - 1) / 2dy) - 1
- = floor((2Ndx + dy + B + 2dy - 1 - 2dy) / 2dy)
- = floor((2Ndx + dy + B - 1) / 2dy)
-\f
-So, our equations are:
-
- 1: X major move x1 to x1+M floor((2Mdy + dx - B) / 2dx)
- 1b: X major move x2 to x1+M floor((2Mdy + dx - B) / 2dx)
- 2: X major move x2 to x2-M floor((2Mdy + dx + B - 1) / 2dx)
- 2b: X major move x1 to x2-M floor((2Mdy + dx + B - 1) / 2dx)
-
- 3: Y major move x1 to x1+M floor((2Mdy - dy + B - 1) / 2dx) + 1
- 3b: Y major move x2 to x1+M floor((2Mdy + dy + B - 1) / 2dx)
- 4: Y major move x2 to x2-M floor((2Mdy - dy - B) / 2dx) + 1
- 4b: Y major move x1 to x2-M floor((2Mdy + dy - B) / 2dx)
-
- 5: X major move y1 to y1+N floor((2Ndx - dx + B - 1) / 2dy) + 1
- 5b: X major move y2 to y1+N floor((2Ndx + dx + B - 1) / 2dy)
- 6: X major move y2 to y2-N floor((2Ndx - dx - B) / 2dy) + 1
- 6b: X major move y1 to y2-N floor((2Ndx + dx - B) / 2dy)
-
- 7: Y major move y1 to y1+N floor((2Ndx + dy - B) / 2dy)
- 7b: Y major move y2 to y1+N floor((2Ndx + dy - B) / 2dy)
- 8: Y major move y2 to y2-N floor((2Ndx + dy + B - 1) / 2dy)
- 8b: Y major move y1 to y2-N floor((2Ndx + dy + B - 1) / 2dy)
-
-We have the following constraints on all of the above terms:
-
- 0 < M,N <= 2^15 2^15 can be imposed by miZeroClipLine
- 0 <= dx/dy <= 2^16 - 1
- 0 <= B <= 1
-
-The floor in all of the above equations can be accomplished with a
-simple C divide operation provided that both numerator and denominator
-are positive.
-
-Since dx,dy >= 0 and since moving an X coordinate implies that dx != 0
-and moving a Y coordinate implies dy != 0, we know that the denominators
-are all > 0.
-
-For all lines, (-B) and (B-1) are both either 0 or -1, depending on the
-bias. Thus, we have to show that the 2MNdxy +/- dxy terms are all >= 1
-or > 0 to prove that the numerators are positive (or zero).
-
-For X Major lines we know that dx > 0 and since 2Mdy is >= 0 due to the
-constraints, the first four equations all have numerators >= 0.
-
-For the second four equations, M > 0, so 2Mdy >= 2dy so (2Mdy - dy) >= dy
-So (2Mdy - dy) > 0, since they are Y major lines. Also, (2Mdy + dy) >= 3dy
-or (2Mdy + dy) > 0. So all of their numerators are >= 0.
-
-For the third set of four equations, N > 0, so 2Ndx >= 2dx so (2Ndx - dx)
->= dx > 0. Similarly (2Ndx + dx) >= 3dx > 0. So all numerators >= 0.
-
-For the fourth set of equations, dy > 0 and 2Ndx >= 0, so all numerators
-are > 0.
-
-To consider overflow, consider the case of 2 * M,N * dx,dy + dx,dy. This
-is bounded <= 2 * 2^15 * (2^16 - 1) + (2^16 - 1)
- <= 2^16 * (2^16 - 1) + (2^16 - 1)
- <= 2^32 - 2^16 + 2^16 - 1
- <= 2^32 - 1
-Since the (-B) and (B-1) terms are all 0 or -1, the maximum value of
-the numerator is therefore (2^32 - 1), which does not overflow an unsigned
-32 bit variable.
-
-*/
-
-#define MIOUTCODES(outcode, x, y, xmin, ymin, xmax, ymax) \
-{\
- if (x < xmin) outcode |= OUT_LEFT;\
- if (x > xmax) outcode |= OUT_RIGHT;\
- if (y < ymin) outcode |= OUT_ABOVE;\
- if (y > ymax) outcode |= OUT_BELOW;\
-}
-
-/* Bit codes for the terms of the 16 clipping equations defined below. */
-
-#define T_2NDX (1 << 0)
-#define T_2MDY (0) /* implicit term */
-#define T_DXNOTY (1 << 1)
-#define T_DYNOTX (0) /* implicit term */
-#define T_SUBDXORY (1 << 2)
-#define T_ADDDX (T_DXNOTY) /* composite term */
-#define T_SUBDX (T_DXNOTY | T_SUBDXORY) /* composite term */
-#define T_ADDDY (T_DYNOTX) /* composite term */
-#define T_SUBDY (T_DYNOTX | T_SUBDXORY) /* composite term */
-#define T_BIASSUBONE (1 << 3)
-#define T_SUBBIAS (0) /* implicit term */
-#define T_DIV2DX (1 << 4)
-#define T_DIV2DY (0) /* implicit term */
-#define T_ADDONE (1 << 5)
-
-/* Bit masks defining the 16 equations used in miZeroClipLine. */
-
-#define EQN1 (T_2MDY | T_ADDDX | T_SUBBIAS | T_DIV2DX)
-#define EQN1B (T_2MDY | T_ADDDX | T_SUBBIAS | T_DIV2DX)
-#define EQN2 (T_2MDY | T_ADDDX | T_BIASSUBONE | T_DIV2DX)
-#define EQN2B (T_2MDY | T_ADDDX | T_BIASSUBONE | T_DIV2DX)
-
-#define EQN3 (T_2MDY | T_SUBDY | T_BIASSUBONE | T_DIV2DX | T_ADDONE)
-#define EQN3B (T_2MDY | T_ADDDY | T_BIASSUBONE | T_DIV2DX)
-#define EQN4 (T_2MDY | T_SUBDY | T_SUBBIAS | T_DIV2DX | T_ADDONE)
-#define EQN4B (T_2MDY | T_ADDDY | T_SUBBIAS | T_DIV2DX)
-
-#define EQN5 (T_2NDX | T_SUBDX | T_BIASSUBONE | T_DIV2DY | T_ADDONE)
-#define EQN5B (T_2NDX | T_ADDDX | T_BIASSUBONE | T_DIV2DY)
-#define EQN6 (T_2NDX | T_SUBDX | T_SUBBIAS | T_DIV2DY | T_ADDONE)
-#define EQN6B (T_2NDX | T_ADDDX | T_SUBBIAS | T_DIV2DY)
-
-#define EQN7 (T_2NDX | T_ADDDY | T_SUBBIAS | T_DIV2DY)
-#define EQN7B (T_2NDX | T_ADDDY | T_SUBBIAS | T_DIV2DY)
-#define EQN8 (T_2NDX | T_ADDDY | T_BIASSUBONE | T_DIV2DY)
-#define EQN8B (T_2NDX | T_ADDDY | T_BIASSUBONE | T_DIV2DY)
-
-/* miZeroClipLine
- *
- * returns: 1 for partially clipped line
- * -1 for completely clipped line
- *
- */
-int
-miZeroClipLine(xmin, ymin, xmax, ymax,
- new_x1, new_y1, new_x2, new_y2,
- adx, ady,
- pt1_clipped, pt2_clipped, octant, bias, oc1, oc2)
- int xmin, ymin, xmax, ymax;
- int *new_x1, *new_y1, *new_x2, *new_y2;
- int *pt1_clipped, *pt2_clipped;
- unsigned int adx, ady;
- int octant;
- unsigned int bias;
- int oc1, oc2;
-{
- int swapped = 0;
- int clipDone = 0;
- CARD32 utmp;
- int clip1, clip2;
- int x1, y1, x2, y2;
- int x1_orig, y1_orig, x2_orig, y2_orig;
- int xmajor;
- int negslope, anchorval;
- unsigned int eqn;
-
- x1 = x1_orig = *new_x1;
- y1 = y1_orig = *new_y1;
- x2 = x2_orig = *new_x2;
- y2 = y2_orig = *new_y2;
-
- clip1 = 0;
- clip2 = 0;
-
- xmajor = IsXMajorOctant(octant);
- bias = ((bias >> octant) & 1);
-
- while (1)
- {
- if ((oc1 & oc2) != 0) /* trivial reject */
- {
- clipDone = -1;
- clip1 = oc1;
- clip2 = oc2;
- break;
- }
- else if ((oc1 | oc2) == 0) /* trivial accept */
- {
- clipDone = 1;
- if (swapped)
- {
- SWAPINT_PAIR(x1, y1, x2, y2);
- SWAPINT(clip1, clip2);
- }
- break;
- }
- else /* have to clip */
- {
- /* only clip one point at a time */
- if (oc1 == 0)
- {
- SWAPINT_PAIR(x1, y1, x2, y2);
- SWAPINT_PAIR(x1_orig, y1_orig, x2_orig, y2_orig);
- SWAPINT(oc1, oc2);
- SWAPINT(clip1, clip2);
- swapped = !swapped;
- }
-
- clip1 |= oc1;
- if (oc1 & OUT_LEFT)
- {
- negslope = IsYDecreasingOctant(octant);
- utmp = xmin - x1_orig;
- if (utmp <= 32767) /* clip based on near endpt */
- {
- if (xmajor)
- eqn = (swapped) ? EQN2 : EQN1;
- else
- eqn = (swapped) ? EQN4 : EQN3;
- anchorval = y1_orig;
- }
- else /* clip based on far endpt */
- {
- utmp = x2_orig - xmin;
- if (xmajor)
- eqn = (swapped) ? EQN1B : EQN2B;
- else
- eqn = (swapped) ? EQN3B : EQN4B;
- anchorval = y2_orig;
- negslope = !negslope;
- }
- x1 = xmin;
- }
- else if (oc1 & OUT_ABOVE)
- {
- negslope = IsXDecreasingOctant(octant);
- utmp = ymin - y1_orig;
- if (utmp <= 32767) /* clip based on near endpt */
- {
- if (xmajor)
- eqn = (swapped) ? EQN6 : EQN5;
- else
- eqn = (swapped) ? EQN8 : EQN7;
- anchorval = x1_orig;
- }
- else /* clip based on far endpt */
- {
- utmp = y2_orig - ymin;
- if (xmajor)
- eqn = (swapped) ? EQN5B : EQN6B;
- else
- eqn = (swapped) ? EQN7B : EQN8B;
- anchorval = x2_orig;
- negslope = !negslope;
- }
- y1 = ymin;
- }
- else if (oc1 & OUT_RIGHT)
- {
- negslope = IsYDecreasingOctant(octant);
- utmp = x1_orig - xmax;
- if (utmp <= 32767) /* clip based on near endpt */
- {
- if (xmajor)
- eqn = (swapped) ? EQN2 : EQN1;
- else
- eqn = (swapped) ? EQN4 : EQN3;
- anchorval = y1_orig;
- }
- else /* clip based on far endpt */
- {
- /*
- * Technically since the equations can handle
- * utmp == 32768, this overflow code isn't
- * needed since X11 protocol can't generate
- * a line which goes more than 32768 pixels
- * to the right of a clip rectangle.
- */
- utmp = xmax - x2_orig;
- if (xmajor)
- eqn = (swapped) ? EQN1B : EQN2B;
- else
- eqn = (swapped) ? EQN3B : EQN4B;
- anchorval = y2_orig;
- negslope = !negslope;
- }
- x1 = xmax;
- }
- else if (oc1 & OUT_BELOW)
- {
- negslope = IsXDecreasingOctant(octant);
- utmp = y1_orig - ymax;
- if (utmp <= 32767) /* clip based on near endpt */
- {
- if (xmajor)
- eqn = (swapped) ? EQN6 : EQN5;
- else
- eqn = (swapped) ? EQN8 : EQN7;
- anchorval = x1_orig;
- }
- else /* clip based on far endpt */
- {
- /*
- * Technically since the equations can handle
- * utmp == 32768, this overflow code isn't
- * needed since X11 protocol can't generate
- * a line which goes more than 32768 pixels
- * below the bottom of a clip rectangle.
- */
- utmp = ymax - y2_orig;
- if (xmajor)
- eqn = (swapped) ? EQN5B : EQN6B;
- else
- eqn = (swapped) ? EQN7B : EQN8B;
- anchorval = x2_orig;
- negslope = !negslope;
- }
- y1 = ymax;
- }
-
- if (swapped)
- negslope = !negslope;
-
- utmp <<= 1; /* utmp = 2N or 2M */
- if (eqn & T_2NDX)
- utmp = (utmp * adx);
- else /* (eqn & T_2MDY) */
- utmp = (utmp * ady);
- if (eqn & T_DXNOTY)
- if (eqn & T_SUBDXORY)
- utmp -= adx;
- else
- utmp += adx;
- else /* (eqn & T_DYNOTX) */
- if (eqn & T_SUBDXORY)
- utmp -= ady;
- else
- utmp += ady;
- if (eqn & T_BIASSUBONE)
- utmp += bias - 1;
- else /* (eqn & T_SUBBIAS) */
- utmp -= bias;
- if (eqn & T_DIV2DX)
- utmp /= (adx << 1);
- else /* (eqn & T_DIV2DY) */
- utmp /= (ady << 1);
- if (eqn & T_ADDONE)
- utmp++;
-
- if (negslope)
- utmp = -utmp;
-
- if (eqn & T_2NDX) /* We are calculating X steps */
- x1 = anchorval + utmp;
- else /* else, Y steps */
- y1 = anchorval + utmp;
-
- oc1 = 0;
- MIOUTCODES(oc1, x1, y1, xmin, ymin, xmax, ymax);
- }
- }
-
- *new_x1 = x1;
- *new_y1 = y1;
- *new_x2 = x2;
- *new_y2 = y2;
-
- *pt1_clipped = clip1;
- *pt2_clipped = clip2;
-
- return clipDone;
-}
-
-
-/* Draw lineSolid, fillStyle-independent zero width lines.
- *
- * Must keep X and Y coordinates in "ints" at least until after they're
- * translated and clipped to accomodate CoordModePrevious lines with very
- * large coordinates.
- *
- * Draws the same pixels regardless of sign(dx) or sign(dy).
- *
- * Ken Whaley
- *
- */
-
-/* largest positive value that can fit into a component of a point.
- * Assumes that the point structure is {type x, y;} where type is
- * a signed type.
- */
-#define MAX_COORDINATE ((1 << (((sizeof(DDXPointRec) >> 1) << 3) - 1)) - 1)
-
-#define MI_OUTPUT_POINT(xx, yy)\
-{\
- if ( !new_span && yy == current_y)\
- {\
- if (xx < spans->x)\
- spans->x = xx;\
- ++*widths;\
- }\
- else\
- {\
- ++Nspans;\
- ++spans;\
- ++widths;\
- spans->x = xx;\
- spans->y = yy;\
- *widths = 1;\
- current_y = yy;\
- new_span = FALSE;\
- }\
-}
-
-void
-miZeroLine(pDraw, pGC, mode, npt, pptInit)
- DrawablePtr pDraw;
- GCPtr pGC;
- int mode; /* Origin or Previous */
- int npt; /* number of points */
- DDXPointPtr pptInit;
-{
- int Nspans, current_y;
- DDXPointPtr ppt;
- DDXPointPtr pspanInit, spans;
- int *pwidthInit, *widths, list_len;
- int xleft, ytop, xright, ybottom;
- int new_x1, new_y1, new_x2, new_y2;
- int x, y, x1, y1, x2, y2, xstart, ystart;
- int oc1, oc2;
- int result;
- int pt1_clipped, pt2_clipped = 0;
- Bool new_span;
- int signdx, signdy;
- int clipdx, clipdy;
- int width, height;
- int adx, ady;
- int octant;
- unsigned int bias = miGetZeroLineBias(pDraw->pScreen);
- int e, e1, e2, e3; /* Bresenham error terms */
- int length; /* length of lines == # of pixels on major axis */
-
- xleft = pDraw->x;
- ytop = pDraw->y;
- xright = pDraw->x + pDraw->width - 1;
- ybottom = pDraw->y + pDraw->height - 1;
-
- if (!pGC->miTranslate)
- {
- /* do everything in drawable-relative coordinates */
- xleft = 0;
- ytop = 0;
- xright -= pDraw->x;
- ybottom -= pDraw->y;
- }
-
- /* it doesn't matter whether we're in drawable or screen coordinates,
- * FillSpans simply cannot take starting coordinates outside of the
- * range of a DDXPointRec component.
- */
- if (xright > MAX_COORDINATE)
- xright = MAX_COORDINATE;
- if (ybottom > MAX_COORDINATE)
- ybottom = MAX_COORDINATE;
-
- /* since we're clipping to the drawable's boundaries & coordinate
- * space boundaries, we're guaranteed that the larger of width/height
- * is the longest span we'll need to output
- */
- width = xright - xleft + 1;
- height = ybottom - ytop + 1;
- list_len = (height >= width) ? height : width;
- pspanInit = (DDXPointPtr)ALLOCATE_LOCAL(list_len * sizeof(DDXPointRec));
- pwidthInit = (int *)ALLOCATE_LOCAL(list_len * sizeof(int));
- if (!pspanInit || !pwidthInit)
- return;
-
- Nspans = 0;
- new_span = TRUE;
- spans = pspanInit - 1;
- widths = pwidthInit - 1;
- ppt = pptInit;
-
- xstart = ppt->x;
- ystart = ppt->y;
- if (pGC->miTranslate)
- {
- xstart += pDraw->x;
- ystart += pDraw->y;
- }
-
- /* x2, y2, oc2 copied to x1, y1, oc1 at top of loop to simplify
- * iteration logic
- */
- x2 = xstart;
- y2 = ystart;
- oc2 = 0;
- MIOUTCODES(oc2, x2, y2, xleft, ytop, xright, ybottom);
-
- while (--npt > 0)
- {
- if (Nspans > 0)
- (*pGC->ops->FillSpans)(pDraw, pGC, Nspans, pspanInit,
- pwidthInit, FALSE);
- Nspans = 0;
- new_span = TRUE;
- spans = pspanInit - 1;
- widths = pwidthInit - 1;
-
- x1 = x2;
- y1 = y2;
- oc1 = oc2;
- ++ppt;
-
- x2 = ppt->x;
- y2 = ppt->y;
- if (pGC->miTranslate && (mode != CoordModePrevious))
- {
- x2 += pDraw->x;
- y2 += pDraw->y;
- }
- else if (mode == CoordModePrevious)
- {
- x2 += x1;
- y2 += y1;
- }
-
- oc2 = 0;
- MIOUTCODES(oc2, x2, y2, xleft, ytop, xright, ybottom);
-
- CalcLineDeltas(x1, y1, x2, y2, adx, ady, signdx, signdy, 1, 1, octant);
-
- if (adx > ady)
- {
- e1 = ady << 1;
- e2 = e1 - (adx << 1);
- e = e1 - adx;
- length = adx; /* don't draw endpoint in main loop */
-
- FIXUP_ERROR(e, octant, bias);
-
- new_x1 = x1;
- new_y1 = y1;
- new_x2 = x2;
- new_y2 = y2;
- pt1_clipped = 0;
- pt2_clipped = 0;
-
- if ((oc1 | oc2) != 0)
- {
- result = miZeroClipLine(xleft, ytop, xright, ybottom,
- &new_x1, &new_y1, &new_x2, &new_y2,
- adx, ady,
- &pt1_clipped, &pt2_clipped,
- octant, bias, oc1, oc2);
- if (result == -1)
- continue;
-
- length = abs(new_x2 - new_x1);
-
- /* if we've clipped the endpoint, always draw the full length
- * of the segment, because then the capstyle doesn't matter
- */
- if (pt2_clipped)
- length++;
-
- if (pt1_clipped)
- {
- /* must calculate new error terms */
- clipdx = abs(new_x1 - x1);
- clipdy = abs(new_y1 - y1);
- e += (clipdy * e2) + ((clipdx - clipdy) * e1);
- }
- }
-
- /* draw the segment */
-
- x = new_x1;
- y = new_y1;
-
- e3 = e2 - e1;
- e = e - e1;
-
- while (length--)
- {
- MI_OUTPUT_POINT(x, y);
- e += e1;
- if (e >= 0)
- {
- y += signdy;
- e += e3;
- }
- x += signdx;
- }
- }
- else /* Y major line */
- {
- e1 = adx << 1;
- e2 = e1 - (ady << 1);
- e = e1 - ady;
- length = ady; /* don't draw endpoint in main loop */
-
- SetYMajorOctant(octant);
- FIXUP_ERROR(e, octant, bias);
-
- new_x1 = x1;
- new_y1 = y1;
- new_x2 = x2;
- new_y2 = y2;
- pt1_clipped = 0;
- pt2_clipped = 0;
-
- if ((oc1 | oc2) != 0)
- {
- result = miZeroClipLine(xleft, ytop, xright, ybottom,
- &new_x1, &new_y1, &new_x2, &new_y2,
- adx, ady,
- &pt1_clipped, &pt2_clipped,
- octant, bias, oc1, oc2);
- if (result == -1)
- continue;
-
- length = abs(new_y2 - new_y1);
-
- /* if we've clipped the endpoint, always draw the full length
- * of the segment, because then the capstyle doesn't matter
- */
- if (pt2_clipped)
- length++;
-
- if (pt1_clipped)
- {
- /* must calculate new error terms */
- clipdx = abs(new_x1 - x1);
- clipdy = abs(new_y1 - y1);
- e += (clipdx * e2) + ((clipdy - clipdx) * e1);
- }
- }
-
- /* draw the segment */
-
- x = new_x1;
- y = new_y1;
-
- e3 = e2 - e1;
- e = e - e1;
-
- while (length--)
- {
- MI_OUTPUT_POINT(x, y);
- e += e1;
- if (e >= 0)
- {
- x += signdx;
- e += e3;
- }
- y += signdy;
- }
- }
- }
-
- /* only do the capnotlast check on the last segment
- * and only if the endpoint wasn't clipped. And then, if the last
- * point is the same as the first point, do not draw it, unless the
- * line is degenerate
- */
- if ( (! pt2_clipped) && (pGC->capStyle != CapNotLast) &&
- (((xstart != x2) || (ystart != y2)) || (ppt == pptInit + 1)))
- {
- MI_OUTPUT_POINT(x, y);
- }
-
- if (Nspans > 0)
- (*pGC->ops->FillSpans)(pDraw, pGC, Nspans, pspanInit,
- pwidthInit, FALSE);
-
- DEALLOCATE_LOCAL(pwidthInit);
- DEALLOCATE_LOCAL(pspanInit);
-}
-
-void
-miZeroDashLine(dst, pgc, mode, nptInit, pptInit)
-DrawablePtr dst;
-GCPtr pgc;
-int mode;
-int nptInit; /* number of points in polyline */
-DDXPointRec *pptInit; /* points in the polyline */
-{
- /* XXX kludge until real zero-width dash code is written */
- pgc->lineWidth = 1;
- miWideDash (dst, pgc, mode, nptInit, pptInit);
- pgc->lineWidth = 0;
-}
projects / rdpsrv / blobdiff