xserver: Branch 'master' - 2 commits
Søren Sandmann Pedersen
sandmann at kemper.freedesktop.org
Mon Apr 23 21:21:48 EEST 2007
fb/fbcompose.c | 203 ++++++++++++++++++++++++++++++++++++++++++++--------
render/picture.c | 29 +++----
render/picturestr.h | 23 ++++-
3 files changed, 202 insertions(+), 53 deletions(-)
New commits:
diff-tree b5e1f7869b2f12a1c2baa7f699ae609fc9ad50aa (from 84838268b34661d598f8e4856fab355f414930d9)
Author: Soren Sandmann Pedersen <ssp at dhcp83-218.boston.redhat.com>
Date: Mon Apr 23 14:16:30 2007 -0400
Remove #if 0'ed merge leftovers
diff --git a/render/picture.c b/render/picture.c
index 201ceb2..2022175 100644
--- a/render/picture.c
+++ b/render/picture.c
@@ -1051,23 +1051,6 @@ CreateRadialGradientPicture (Picture pid
radial = &pPicture->pSourcePict->radial;
radial->type = SourcePictTypeRadial;
-#if 0
- {
- double x = (double)innerRadius / (double)outerRadius;
- radial->dx = (outer->x - inner->x);
- radial->dy = (outer->y - inner->y);
- radial->fx = (inner->x) - x*radial->dx;
- radial->fy = (inner->y) - x*radial->dy;
- radial->m = 1./(1+x);
- radial->b = -x*radial->m;
- radial->dx /= 65536.;
- radial->dy /= 65536.;
- radial->fx /= 65536.;
- radial->fy /= 65536.;
- x = outerRadius/65536.;
- radial->a = x*x - radial->dx*radial->dx - radial->dy*radial->dy;
- }
-#endif
radial->c1.x = inner->x;
radial->c1.y = inner->y;
radial->c1.radius = innerRadius;
diff-tree 84838268b34661d598f8e4856fab355f414930d9 (from 38d14e858980a1b0c087344d24bf6aebf755663c)
Author: Soren Sandmann Pedersen <ssp at dhcp83-218.boston.redhat.com>
Date: Mon Apr 23 13:19:54 2007 -0400
Gradient fixes
* Port fix for bug 7685 from pixman. Patch by Carl Worth
* Add projective version of radial gradient code.
* Make sure that all Pict*Gradient types have PictGradient as prefix,
since code in various places relies on that.
diff --git a/fb/fbcompose.c b/fb/fbcompose.c
index 0faf783..24b552e 100644
--- a/fb/fbcompose.c
+++ b/fb/fbcompose.c
@@ -3148,13 +3148,128 @@ static void fbFetchSourcePict(PicturePtr
}
}
} else {
+
+/*
+ * In the radial gradient problem we are given two circles (câ‚,râ‚) and
+ * (câ‚‚,râ‚‚) that define the gradient itself. Then, for any point p, we
+ * must compute the value(s) of t within [0.0, 1.0] representing the
+ * circle(s) that would color the point.
+ *
+ * There are potentially two values of t since the point p can be
+ * colored by both sides of the circle, (which happens whenever one
+ * circle is not entirely contained within the other).
+ *
+ * If we solve for a value of t that is outside of [0.0, 1.0] then we
+ * use the extend mode (NONE, REPEAT, REFLECT, or PAD) to map to a
+ * value within [0.0, 1.0].
+ *
+ * Here is an illustration of the problem:
+ *
+ * pâ‚‚
+ * p •
+ * • ╲
+ * · ╲r₂
+ * p₠· ╲
+ * • θ╲
+ * ╲ ╌╌•
+ * ╲r₠· c₂
+ * θ╲ ·
+ * ╌╌•
+ * câ‚
+ *
+ * Given (câ‚,râ‚), (câ‚‚,râ‚‚) and p, we must find an angle θ such that two
+ * points pâ‚ and pâ‚‚ on the two circles are collinear with p. Then, the
+ * desired value of t is the ratio of the length of pâ‚p to the length
+ * of pâ‚pâ‚‚.
+ *
+ * So, we have six unknown values: (pâ‚x, pâ‚y), (pâ‚‚x, pâ‚‚y), θ and t.
+ * We can also write six equations that constrain the problem:
+ *
+ * Point p₠is a distance r₠from c₠at an angle of θ:
+ *
+ * 1. pâ‚x = câ‚x + râ‚·cos θ
+ * 2. pâ‚y = câ‚y + râ‚·sin θ
+ *
+ * Point p₂ is a distance r₂ from c₂ at an angle of θ:
+ *
+ * 3. p₂x = c₂x + r2·cos θ
+ * 4. p₂y = c₂y + r2·sin θ
+ *
+ * Point p lies at a fraction t along the line segment pâ‚pâ‚‚:
+ *
+ * 5. px = t·pâ‚‚x + (1-t)·pâ‚x
+ * 6. py = t·pâ‚‚y + (1-t)·pâ‚y
+ *
+ * To solve, first subtitute 1-4 into 5 and 6:
+ *
+ * px = t·(câ‚‚x + r₂·cos θ) + (1-t)·(câ‚x + râ‚·cos θ)
+ * py = t·(câ‚‚y + r₂·sin θ) + (1-t)·(câ‚y + râ‚·sin θ)
+ *
+ * Then solve each for cos θ and sin θ expressed as a function of t:
+ *
+ * cos θ = (-(câ‚‚x - câ‚x)·t + (px - câ‚x)) / ((râ‚‚-râ‚)·t + râ‚)
+ * sin θ = (-(câ‚‚y - câ‚y)·t + (py - câ‚y)) / ((râ‚‚-râ‚)·t + râ‚)
+ *
+ * To simplify this a bit, we define new variables for several of the
+ * common terms as shown below:
+ *
+ * pâ‚‚
+ * p •
+ * • ╲
+ * · ┆ ╲r₂
+ * p₠· ┆ ╲
+ * • pdy┆ ╲
+ * ╲ ┆ •c₂
+ * ╲r₠┆ · ┆
+ * ╲ ·┆ ┆cdy
+ * •╌╌╌╌┴╌╌╌╌╌╌╌┘
+ * câ‚ pdx cdx
+ *
+ * cdx = (câ‚‚x - câ‚x)
+ * cdy = (câ‚‚y - câ‚y)
+ * dr = râ‚‚-râ‚
+ * pdx = px - câ‚x
+ * pdy = py - câ‚y
+ *
+ * Note that cdx, cdy, and dr do not depend on point p at all, so can
+ * be pre-computed for the entire gradient. The simplifed equations
+ * are now:
+ *
+ * cos θ = (-cdx·t + pdx) / (dr·t + râ‚)
+ * sin θ = (-cdy·t + pdy) / (dr·t + râ‚)
+ *
+ * Finally, to get a single function of t and eliminate the last
+ * unknown θ, we use the identity sin²θ + cos²θ = 1. First, square
+ * each equation, (we knew a quadratic was coming since it must be
+ * possible to obtain two solutions in some cases):
+ *
+ * cos²θ = (cdx²t² - 2·cdx·pdx·t + pdx²) / (dr²·t² + 2·râ‚·dr·t + r₲)
+ * sin²θ = (cdy²t² - 2·cdy·pdy·t + pdy²) / (dr²·t² + 2·râ‚·dr·t + r₲)
+ *
+ * Then add both together, set the result equal to 1, and express as a
+ * standard quadratic equation in t of the form At² + Bt + C = 0
+ *
+ * (cdx² + cdy² - dr²)·t² - 2·(cdx·pdx + cdy·pdy + râ‚·dr)·t + (pdx² + pdy² - r₲) = 0
+ *
+ * In other words:
+ *
+ * A = cdx² + cdy² - dr²
+ * B = -2·(pdx·cdx + pdy·cdy + râ‚·dr)
+ * C = pdx² + pdy² - r₲
+ *
+ * And again, notice that A does not depend on p, so can be
+ * precomputed. From here we just use the quadratic formula to solve
+ * for t:
+ *
+ * t = (-2·B ± ⎷(B² - 4·A·C)) / 2·A
+ */
/* radial or conical */
Bool affine = TRUE;
double cx = 1.;
double cy = 0.;
double cz = 0.;
- double rx = x;
- double ry = y;
+ double rx = x + 0.5;
+ double ry = y + 0.5;
double rz = 1.;
if (pict->transform) {
@@ -3176,25 +3291,38 @@ static void fbFetchSourcePict(PicturePtr
}
if (pGradient->type == SourcePictTypeRadial) {
+ PictRadialGradient *radial;
+ radial = &pGradient->radial;
if (affine) {
- rx -= pGradient->radial.fx;
- ry -= pGradient->radial.fy;
-
while (buffer < end) {
- double b, c, det, s;
-
if (!mask || *mask++ & maskBits)
{
- xFixed_48_16 t;
+ double pdx, pdy;
+ double B, C;
+ double det;
+ double c1x = radial->c1.x / 65536.0;
+ double c1y = radial->c1.y / 65536.0;
+ double r1 = radial->c1.radius / 65536.0;
+ xFixed_48_16 t;
+
+ pdx = rx - c1x;
+ pdy = ry - c1y;
+
+ B = -2 * ( pdx * radial->cdx
+ + pdy * radial->cdy
+ + r1 * radial->dr);
+ C = (pdx * pdx + pdy * pdy - r1 * r1);
+
+ det = (B * B) - (4 * radial->A * C);
+ if (det < 0.0)
+ det = 0.0;
+
+ if (radial->A < 0)
+ t = (xFixed_48_16) ((- B - sqrt(det)) / (2.0 * radial->A) * 65536);
+ else
+ t = (xFixed_48_16) ((- B + sqrt(det)) / (2.0 * radial->A) * 65536);
- b = 2*(rx*pGradient->radial.dx + ry*pGradient->radial.dy);
- c = -(rx*rx + ry*ry);
- det = (b * b) - (4 * pGradient->radial.a * c);
- s = (-b + sqrt(det))/(2. * pGradient->radial.a);
-
- t = (xFixed_48_16)((s*pGradient->radial.m + pGradient->radial.b)*65536);
-
- WRITE(buffer, _gradient_walker_pixel (&walker, t));
+ WRITE(buffer, _gradient_walker_pixel (&walker, t));
}
++buffer;
@@ -3202,35 +3330,50 @@ static void fbFetchSourcePict(PicturePtr
ry += cy;
}
} else {
+ /* projective */
while (buffer < end) {
- double x, y;
- double b, c, det, s;
-
if (!mask || *mask++ & maskBits)
{
- xFixed_48_16 t;
-
+ double pdx, pdy;
+ double B, C;
+ double det;
+ double c1x = radial->c1.x / 65536.0;
+ double c1y = radial->c1.y / 65536.0;
+ double r1 = radial->c1.radius / 65536.0;
+ xFixed_48_16 t;
+ double x, y;
+
if (rz != 0) {
x = rx/rz;
y = ry/rz;
} else {
x = y = 0.;
}
- x -= pGradient->radial.fx;
- y -= pGradient->radial.fy;
- b = 2*(x*pGradient->radial.dx + y*pGradient->radial.dy);
- c = -(x*x + y*y);
- det = (b * b) - (4 * pGradient->radial.a * c);
- s = (-b + sqrt(det))/(2. * pGradient->radial.a);
- t = (xFixed_48_16)((s*pGradient->radial.m + pGradient->radial.b)*65536);
- WRITE(buffer, _gradient_walker_pixel (&walker, t));
+ pdx = x - c1x;
+ pdy = y - c1y;
+
+ B = -2 * ( pdx * radial->cdx
+ + pdy * radial->cdy
+ + r1 * radial->dr);
+ C = (pdx * pdx + pdy * pdy - r1 * r1);
+
+ det = (B * B) - (4 * radial->A * C);
+ if (det < 0.0)
+ det = 0.0;
+
+ if (radial->A < 0)
+ t = (xFixed_48_16) ((- B - sqrt(det)) / (2.0 * radial->A) * 65536);
+ else
+ t = (xFixed_48_16) ((- B + sqrt(det)) / (2.0 * radial->A) * 65536);
+
+ WRITE(buffer, _gradient_walker_pixel (&walker, t));
}
++buffer;
rx += cx;
ry += cy;
- rz += cz;
+ rz += cz;
}
}
} else /* SourcePictTypeConical */ {
diff --git a/render/picture.c b/render/picture.c
index 3f64182..201ceb2 100644
--- a/render/picture.c
+++ b/render/picture.c
@@ -1051,6 +1051,7 @@ CreateRadialGradientPicture (Picture pid
radial = &pPicture->pSourcePict->radial;
radial->type = SourcePictTypeRadial;
+#if 0
{
double x = (double)innerRadius / (double)outerRadius;
radial->dx = (outer->x - inner->x);
@@ -1066,7 +1067,20 @@ CreateRadialGradientPicture (Picture pid
x = outerRadius/65536.;
radial->a = x*x - radial->dx*radial->dx - radial->dy*radial->dy;
}
-
+#endif
+ radial->c1.x = inner->x;
+ radial->c1.y = inner->y;
+ radial->c1.radius = innerRadius;
+ radial->c2.x = outer->x;
+ radial->c2.y = outer->y;
+ radial->c2.radius = outerRadius;
+ radial->cdx = (radial->c2.x - radial->c1.x) / 65536.;
+ radial->cdy = (radial->c2.y - radial->c1.y) / 65536.;
+ radial->dr = (radial->c2.radius - radial->c1.radius) / 65536.;
+ radial->A = ( radial->cdx * radial->cdx
+ + radial->cdy * radial->cdy
+ - radial->dr * radial->dr);
+
initGradient(pPicture->pSourcePict, nStops, stops, colors, error);
if (*error) {
xfree(pPicture);
diff --git a/render/picturestr.h b/render/picturestr.h
index 3f3c600..6268768 100644
--- a/render/picturestr.h
+++ b/render/picturestr.h
@@ -105,17 +105,26 @@ typedef struct _PictLinearGradient {
xPointFixed p2;
} PictLinearGradient, *PictLinearGradientPtr;
+typedef struct _PictCircle {
+ xFixed x;
+ xFixed y;
+ xFixed radius;
+} PictCircle, *PictCirclePtr;
+
typedef struct _PictRadialGradient {
unsigned int type;
+ unsigned int class;
int nstops;
PictGradientStopPtr stops;
- double fx;
- double fy;
- double dx;
- double dy;
- double a;
- double m;
- double b;
+ int stopRange;
+ CARD32 *colorTable;
+ int colorTableSize;
+ PictCircle c1;
+ PictCircle c2;
+ double cdx;
+ double cdy;
+ double dr;
+ double A;
} PictRadialGradient, *PictRadialGradientPtr;
typedef struct _PictConicalGradient {
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