summaryrefslogtreecommitdiffstats
path: root/chalk/core/kis_filter_strategy.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'chalk/core/kis_filter_strategy.cpp')
-rw-r--r--chalk/core/kis_filter_strategy.cpp192
1 files changed, 192 insertions, 0 deletions
diff --git a/chalk/core/kis_filter_strategy.cpp b/chalk/core/kis_filter_strategy.cpp
new file mode 100644
index 000000000..650a96812
--- /dev/null
+++ b/chalk/core/kis_filter_strategy.cpp
@@ -0,0 +1,192 @@
+/*
+ * Copyright (c) 2004 Michael Thaler <michael.thaler@physik.tu-muenchen.de>
+ * Copyright (c) 2005 Casper Boemann <cbr@boemann.dk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#include <kdebug.h>
+#include <tdelocale.h>
+#include "kis_debug_areas.h"
+#include "kis_filter_strategy.h"
+#include <math.h>
+
+double KisHermiteFilterStrategy::valueAt(double t) const {
+ /* f(t) = 2|t|^3 - 3|t|^2 + 1, -1 <= t <= 1 */
+ if(t < 0.0) t = -t;
+ if(t < 1.0) return((2.0 * t - 3.0) * t * t + 1.0);
+ return(0.0);
+}
+
+TQ_UINT32 KisHermiteFilterStrategy::intValueAt(TQ_INT32 t) const {
+ /* f(t) = 2|t|^3 - 3|t|^2 + 1, -1 <= t <= 1 */
+ if(t < 0) t = -t;
+ if(t < 256)
+ {
+ t =(2 * t - 3*256) * t * t +(256<<16);
+
+ //go from .24 fixed point to .8 fixedpoint (hack only works with positve numbers, which it is)
+ t = (t + 0x8000) >> 16;
+
+ // go from .8 fixed point to 8bitscale. ie t = (t*255)/256;
+ if(t >= 128)
+ return t - 1;
+ return t;
+ }
+ return(0);
+}
+
+double KisCubicFilterStrategy::valueAt(double x) const {
+ if (x < -2.0)
+ return(0.0);
+ if (x < -1.0)
+ return((2.0+x)*(2.0+x)*(2.0+x)/6.0);
+ if (x < 0.0)
+ return((4.0+x*x*(-6.0-3.0*x))/6.0);
+ if (x < 1.0)
+ return((4.0+x*x*(-6.0+3.0*x))/6.0);
+ if (x < 2.0)
+ return((2.0-x)*(2.0-x)*(2.0-x)/6.0);
+ return(0.0);
+}
+
+TQ_UINT32 KisCubicFilterStrategy::intValueAt(TQ_INT32 x) const {
+ if (x < 2)
+ return 0;
+ if (x < -1)
+ return (2 + x) * (2 + x) * ( 2 + x) / 6;
+ if ( x < 0)
+ return (4 + x * x * ( -6 - 3 * x)) / 6;
+ if (x < 1)
+ return (4 + x * x * ( -6 + 3 * x)) / 6;
+ if (x < 2)
+ return (2 - x) * ( 2 - x) * (2 - x) / 6;
+ return 0;
+}
+
+double KisBoxFilterStrategy::valueAt(double t) const {
+ if((t > -0.5) && (t <= 0.5)) return(1.0);
+ return(0.0);
+}
+
+TQ_UINT32 KisBoxFilterStrategy::intValueAt(TQ_INT32 t) const {
+ /* f(t) = 1, -0.5 < t <= 0.5 */
+ if((t > -128) && (t <= 128))
+ return 255;
+ return 0;
+}
+
+double KisTriangleFilterStrategy::valueAt(double t) const {
+ if(t < 0.0) t = -t;
+ if(t < 1.0) return(1.0 - t);
+ return(0.0);
+}
+
+TQ_UINT32 KisTriangleFilterStrategy::intValueAt(TQ_INT32 t) const {
+ /* f(t) = |t|, -1 <= t <= 1 */
+ if(t < 0) t = -t;
+ if(t < 256)
+ {
+ // calc 256-1 but also go from .8 fixed point to 8bitscale. ie t = (t*255)/256; ie: if(t>=128) return t-1;
+ if(t>=128) return 256 - t;
+ return 255 - t;
+ }
+ return(0);
+}
+
+
+double KisBellFilterStrategy::valueAt(double t) const {
+ if(t < 0) t = -t;
+ if(t < .5) return(.75 - (t * t));
+ if(t < 1.5) {
+ t = (t - 1.5);
+ return(.5 * (t * t));
+ }
+ return(0.0);
+}
+
+double KisBSplineFilterStrategy::valueAt(double t) const {
+ double tt;
+
+ if(t < 0) t = -t;
+ if(t < 1) {
+ tt = t * t;
+ return((.5 * tt * t) - tt + (2.0 / 3.0));
+ } else if(t < 2) {
+ t = 2 - t;
+ return((1.0 / 6.0) * (t * t * t));
+ }
+ return(0.0);
+}
+
+double KisLanczos3FilterStrategy::valueAt(double t) const {
+ if(t < 0) t = -t;
+ if(t < 3.0) return(sinc(t) * sinc(t/3.0));
+ return(0.0);
+}
+
+double KisLanczos3FilterStrategy::sinc(double x) const {
+ const double pi=3.1415926535897932385;
+ x *= pi;
+ if(x != 0) return(sin(x) / x);
+ return(1.0);
+}
+
+double KisMitchellFilterStrategy::valueAt(double t) const {
+ const double B=1.0/3.0;
+ const double C=1.0/3.0;
+ double tt;
+
+ tt = t * t;
+ if(t < 0) t = -t;
+ if(t < 1.0) {
+ t = (((12.0 - 9.0 * B - 6.0 * C) * (t * tt)) + ((-18.0 + 12.0 * B + 6.0 * C) * tt) + (6.0 - 2 * B));
+ return(t / 6.0);
+ } else if(t < 2.0) {
+ t = (((-1.0 * B - 6.0 * C) * (t * tt)) + ((6.0 * B + 30.0 * C) * tt) + ((-12.0 * B - 48.0 * C) * t) + (8.0 * B + 24 * C));
+ return(t / 6.0);
+ }
+ return(0.0);
+}
+
+KisFilterStrategyRegistry *KisFilterStrategyRegistry::m_singleton = 0;
+
+KisFilterStrategyRegistry::KisFilterStrategyRegistry()
+{
+ Q_ASSERT(KisFilterStrategyRegistry::m_singleton == 0);
+ KisFilterStrategyRegistry::m_singleton = this;
+}
+
+KisFilterStrategyRegistry::~KisFilterStrategyRegistry()
+{
+}
+
+KisFilterStrategyRegistry* KisFilterStrategyRegistry::instance()
+{
+ if(KisFilterStrategyRegistry::m_singleton == 0)
+ {
+ KisFilterStrategyRegistry::m_singleton = new KisFilterStrategyRegistry();
+ TQ_CHECK_PTR(KisFilterStrategyRegistry::m_singleton);
+ m_singleton->add(new KisHermiteFilterStrategy);
+ m_singleton->add(new KisBoxFilterStrategy);
+ m_singleton->add(new KisTriangleFilterStrategy);
+ m_singleton->add(new KisBellFilterStrategy);
+ m_singleton->add(new KisBSplineFilterStrategy);
+// m_singleton->add(new KisLanczos3FilterStrategy);
+ m_singleton->add(new KisMitchellFilterStrategy);
+// m_singleton->add(new KisCubicFilterStrategy);
+ }
+ return KisFilterStrategyRegistry::m_singleton;
+}
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-01 09:46:56 +0000