remove bilinear interpolation

2 files changed, 14 insertions, 59 deletions

diff --git a/src/GipfelWidget.H b/src/GipfelWidget.H
index ed251ef..0ddfbef 100644
--- a/src/GipfelWidget.H
+++ b/src/GipfelWidget.H
@@ -41,9 +41,6 @@ class GipfelWidget : public Fl_Widget {
 		static int get_pixel_nearest(Fl_Image *img, double x, double y,
 			int *r, int *g, int *b);
 
-		static int get_pixel_bilinear(Fl_Image *img, double x, double y,
-			int *r, int *g, int *b);
-
 		static int get_pixel_bicubic(Fl_Image *img, double x, double y,
 			int *r, int *g, int *b);
 
@@ -53,8 +50,7 @@ class GipfelWidget : public Fl_Widget {
 	public:
 		typedef enum {
 			NEAREST  = 0,
-			BILINEAR = 1,
-			BICUBIC  = 2
+			BICUBIC  = 1
 		} sample_mode_t;
 	
 		GipfelWidget(int X,int Y,int W, int H);
diff --git a/src/GipfelWidget.cxx b/src/GipfelWidget.cxx
index 2daea2a..73be7e2 100644
--- a/src/GipfelWidget.cxx
+++ b/src/GipfelWidget.cxx
@@ -683,10 +683,7 @@ GipfelWidget::get_pixel(GipfelWidget::sample_mode_t m,
 		return 1;
 	}
 
-	if (m == GipfelWidget::BILINEAR) {
-		ret = get_pixel_bilinear(img, px + ((double) img->w()) / 2.0,
-			py + ((double) img->h()) / 2.0, r, g, b);
-	} else if (m == GipfelWidget::BICUBIC) {
+	if (m == GipfelWidget::BICUBIC) {
 		ret = get_pixel_bicubic(img, px + ((double) img->w()) / 2.0,
 			py + ((double) img->h()) / 2.0, r, g, b);
 	} else {
@@ -715,71 +712,33 @@ GipfelWidget::get_pixel_nearest(Fl_Image *img, double x, double y,
 	}
 }
 
-int
-GipfelWidget::get_pixel_bilinear(Fl_Image *img, double x, double y,
-	int *r, int *g, int *b) {
-	int a_r[4] = {0, 0, 0, 0};
-	int a_g[4] = {0, 0, 0, 0};
-	int a_b[4] = {0, 0, 0, 0};
-	float v0 , v1;
-	int fl_x = (int) floor(x);
-	int fl_y = (int) floor(y);
-	int i, n;
-
-	i = 0;
-	n = 0;
-	for (int iy = 0; iy <= 1; iy++) {
-		for (int ix = 0; ix <= 1; ix++) {
-			n += get_pixel(img, fl_x + ix, fl_y + iy, &(a_r[i]), &(a_g[i]), &(a_b[i]));
-			i++;
-		}
-	}
-
-	v0 = a_r[0] * (1 - (x - fl_x)) + a_r[1] * (x - fl_x);
-	v1 = a_r[2] * (1 - (x - fl_x)) + a_r[3] * (x - fl_x);
-	*r = (int) rint(v0 * (1 - (y - fl_y)) + v1 * (y - fl_y));
-
-	v0 = a_g[0] * (1 - (x - fl_x)) + a_g[1] * (x - fl_x);
-	v1 = a_g[2] * (1 - (x - fl_x)) + a_g[3] * (x - fl_x);
-	*g = (int) rint(v0 * (1 - (y - fl_y)) + v1 * (y - fl_y));
-
-	v0 = a_b[0] * (1 - (x - fl_x)) + a_b[1] * (x - fl_x);
-	v1 = a_b[2] * (1 - (x - fl_x)) + a_b[3] * (x - fl_x);
-	*b = (int) rint(v0 * (1 - (y - fl_y)) + v1 * (y - fl_y));
-
-	if (n >= 1) {
-		return 1;
-	} else {
-		return 0;
-	}
-}
-
-static double
-interp_cubic(double x, double *v) {
+static inline double
+interp_cubic(double x, double x2, double x3, double *v) {
 	double a0, a1, a2, a3;
-	double x2 = x * x;
 
 	a0 = v[3] - v[2] - v[0] + v[1];
 	a1 = v[0] - v[1] - a0;
 	a2 = v[2] - v[0];
 	a3 = v[1];
 
-	return a0 * x * x2 +a1 * x2 + a2 * x + a3;
+	return a0 * x3 + a1 * x2 + a2 * x + a3;
 }
 
 int
 GipfelWidget::get_pixel_bicubic(Fl_Image *img, double x, double y,
 	int *r, int *g, int *b) {
 
-	int fl_x = (int) rint(x);
-	int fl_y = (int) rint(y);
+	double fl_x = floor(x);
+	double fl_y = floor(y);
+	double dx = x - fl_x, dx2 = dx * dx, dx3 = dx2 * dx;
+	double dy = y - fl_y, dy2 = dy * dy, dy3 = dy2 * dy;
 	int ic[3];
 	double c[3][4];
 	double c1[3][4];
 
 	for (int iy = 0; iy < 4; iy++) {
 		for (int ix = 0; ix < 4; ix++) {
-			if (get_pixel(img, fl_x + ix - 2, fl_y + iy - 2,
+			if (get_pixel(img, (int) fl_x + ix, (int) fl_y + iy,
 					&ic[0], &ic[1], &ic[2]) != 0) {
 				return 1;
 			}
@@ -790,13 +749,13 @@ GipfelWidget::get_pixel_bicubic(Fl_Image *img, double x, double y,
 		}
 
 		for (int l = 0; l < 3; l++) {
-			c1[l][iy] = interp_cubic(x - fl_x, c[l]);
+			c1[l][iy] = interp_cubic(dx, dx2, dx3, c[l]);
 		}
 	}
 
-	*r = (int) rint(interp_cubic(x - fl_x, c1[0]));
-	*g = (int) rint(interp_cubic(x - fl_x, c1[1]));
-	*b = (int) rint(interp_cubic(x - fl_x, c1[2]));
+	*r = (int) rint(interp_cubic(dy, dy2, dy3, c1[0]));
+	*g = (int) rint(interp_cubic(dy, dy2, dy3, c1[1]));
+	*b = (int) rint(interp_cubic(dy, dy2, dy3, c1[2]));
 
 	return 0;
 }