From ceec61fe9614b7fb631781c3f9d21894e084077b Mon Sep 17 00:00:00 2001
From: Johannes Hofmann <Johannes.Hofmann@gmx.de>
Date: Thu, 14 Sep 2006 14:01:33 +0200
Subject: implement biliear resampling

---
 src/GipfelWidget.H   |  9 ++++++---
 src/GipfelWidget.cxx | 46 ++++++++++++++++++++++++++++++++++++++++++----
 src/Stitch.cxx       |  2 +-
 3 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/src/GipfelWidget.H b/src/GipfelWidget.H
index 7bcd3c0..054e9ef 100644
--- a/src/GipfelWidget.H
+++ b/src/GipfelWidget.H
@@ -48,10 +48,13 @@ class GipfelWidget : public Fl_Widget {
   int get_rel_track_width(Hill *m);
 
   static int get_pixel_nearest(Fl_Image *img, double x, double y,
-                     char *r, char *g, char *b);
+                     uchar *r, uchar *g, uchar *b);
+
+  static int get_pixel_bilinear(Fl_Image *img, double x, double y,
+                     uchar *r, uchar *g, uchar *b);
 
   static int get_pixel(Fl_Image *img, int x, int y,
-                     char *r, char *g, char *b);
+                     uchar *r, uchar *g, uchar *b);
 
  public:
   GipfelWidget(int X,int Y,int W, int H);
@@ -125,7 +128,7 @@ class GipfelWidget : public Fl_Widget {
   int update();
 
   int get_pixel(double a_view, double a_nick,
-                    char *r, char *g, char *b);
+                    uchar *r, uchar *g, uchar *b);
 
   void draw();
 };
diff --git a/src/GipfelWidget.cxx b/src/GipfelWidget.cxx
index 75451ec..272189c 100644
--- a/src/GipfelWidget.cxx
+++ b/src/GipfelWidget.cxx
@@ -748,7 +748,7 @@ GipfelWidget::handle(int event) {
 
 int
 GipfelWidget::get_pixel(double a_view, double a_nick,
-                        char *r, char *g, char *b) {
+                        uchar *r, uchar *g, uchar *b) {
 	double px, py;
 
 
@@ -760,13 +760,13 @@ GipfelWidget::get_pixel(double a_view, double a_nick,
 		return 1;
 	}
 
-	return get_pixel_nearest(img, px + ((double) img->w()) / 2.0,
+	return get_pixel_bilinear(img, px + ((double) img->w()) / 2.0,
 				py + ((double) img->h()) / 2.0, r, g, b);
 }
 
 int
 GipfelWidget::get_pixel_nearest(Fl_Image *img, double x, double y,
-	char *r, char *g, char *b) {
+	uchar *r, uchar *g, uchar *b) {
 	if (isnan(x) || isnan(y)) {
 		return 1;
 	} else {
@@ -774,10 +774,48 @@ GipfelWidget::get_pixel_nearest(Fl_Image *img, double x, double y,
 	}
 }
 
+int
+GipfelWidget::get_pixel_bilinear(Fl_Image *img, double x, double y,
+	uchar *r, uchar *g, uchar *b) {
+	uchar a_r[4] = {0, 0, 0, 0};
+	uchar a_g[4] = {0, 0, 0, 0};
+	uchar 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 = (uchar) 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 = (uchar) 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 = (uchar) rint(v0 * (1 - (y - fl_y)) + v1 * (y - fl_y));
+
+	if (n >= 1) {
+		return 1;
+	} else {
+		return 0;
+	}
+}
 
 int
 GipfelWidget::get_pixel(Fl_Image *img, int x, int y,
-                     char *r, char *g, char *b) {
+                     uchar *r, uchar *g, uchar *b) {
     if ( img->d() == 0 ) {
         return 1;
     }
diff --git a/src/Stitch.cxx b/src/Stitch.cxx
index af46968..f8f77fb 100644
--- a/src/Stitch.cxx
+++ b/src/Stitch.cxx
@@ -93,7 +93,7 @@ int
 Stitch::resample(int w, int h,
             double view_start, double view_end) {
 	double step_view = (view_end - view_start) / w;
-	char r, g, b;
+	uchar r, g, b;
 	int y_off = h / 2;
 	int merged_pixel_set;
  	double radius = (double) w / (view_end -view_start);
-- 
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