Issue 2147: white balance slider now non-linear

rtgui/adjuster.cc

@@ -27,7 +27,9 @@
 
 #define MIN_RESET_BUTTON_HEIGHT 17
 
-Adjuster::Adjuster (Glib::ustring vlabel, double vmin, double vmax, double vstep, double vdefault, Gtk::Image *imgIcon) {
+static double one2one(double val) { return val; }
+
+Adjuster::Adjuster (Glib::ustring vlabel, double vmin, double vmax, double vstep, double vdefault, Gtk::Image *imgIcon, double2double_fun slider2value_, double2double_fun value2slider_) {
 
   Gtk::HBox *hbox2=NULL;
 
@@ -37,6 +39,8 @@ Adjuster::Adjuster (Glib::ustring vlabel, double vmin, double vmax, double vstep
   automatic = NULL;
   eventPending = false;
 
+  slider2value = slider2value_ ? slider2value_ : one2one;
+  value2slider = value2slider_ ? value2slider_ : one2one;
   vMin = vmin;
   vMax = vmax;
   vStep = vstep;
@@ -224,14 +228,14 @@ void Adjuster::resetValue (bool toInitial) {
     afterReset = true;
     if (toInitial) {
         // resetting to the initial editing value, when the image has been loaded
-        slider->set_value (defaultVal);
+	slider->set_value (addMode ? defaultVal : value2slider(defaultVal));
     }
     else {
         // resetting to the slider default value
         if (addMode)
             slider->set_value (0.);
         else
-            slider->set_value (ctorDefaultVal);
+            slider->set_value (value2slider(ctorDefaultVal));
     }
 }
 
@@ -261,8 +265,8 @@ void Adjuster::setLimits (double vmin, double vmax, double vstep, double vdefaul
   spin->set_value (shapeValue(vdefault));
   slider->set_digits (digits);
   slider->set_increments (vstep, 2.0*vstep);
-  slider->set_range (vmin, vmax);
+  slider->set_range (addMode ? vmin : value2slider(vmin), addMode ? vmax : value2slider(vmax));
-  slider->set_value (shapeValue(vdefault));
+  slider->set_value (addMode ? shapeValue(vdefault) : value2slider(shapeValue(vdefault)));
   //defaultVal = shapeValue (vdefault);
   sliderChange.block (false);
   spinChange.block (false);
@@ -271,6 +275,7 @@ void Adjuster::setLimits (double vmin, double vmax, double vstep, double vdefaul
 void Adjuster::setAddMode(bool addM) {
 	if (addM != addMode) {
 		// Switching the Adjuster to the new mode
+		addMode = addM;
 		if (addM) {
 			// Switching to the relative mode
 			double range = -vMin + vMax;
@@ -281,7 +286,6 @@ void Adjuster::setAddMode(bool addM) {
 			// Switching to the absolute mode
 			setLimits(vMin, vMax, vStep, defaultVal);
 		}
-		addMode = addM;
 	}
 }
 
@@ -291,7 +295,7 @@ void Adjuster::spinChanged () {
     delayConnection.disconnect ();
 
   sliderChange.block (true);
-  slider->set_value (spin->get_value ());
+  slider->set_value (addMode ? spin->get_value () : value2slider(spin->get_value ()));
   sliderChange.block (false);
 
   if (delay==0) {
@@ -326,7 +330,7 @@ void Adjuster::sliderChanged () {
     delayConnection.disconnect ();
 
   spinChange.block (true);
-  spin->set_value (slider->get_value ());
+  spin->set_value (addMode ? slider->get_value () : slider2value(slider->get_value ()));
   spinChange.block (false);
 
   if (delay==0 || afterReset) {
@@ -360,7 +364,7 @@ void Adjuster::setValue (double a) {
   spinChange.block (true);
   sliderChange.block (true);
   spin->set_value (shapeValue (a));
-  slider->set_value (shapeValue (a));
+  slider->set_value (addMode ? shapeValue(a) : value2slider(shapeValue (a)));
   sliderChange.block (false);
   spinChange.block (false);
   afterReset = false;

rtgui/adjuster.h

@@ -32,6 +32,7 @@ class AdjusterListener {
     virtual void adjusterAutoToggled (Adjuster* a, bool newval) {}
 };
 
+typedef double(*double2double_fun)(double val);
 
 class Adjuster : public Gtk::VBox {
 
@@ -70,12 +71,13 @@ class Adjuster : public Gtk::VBox {
 
     double shapeValue (double a);
     void   refreshLabelStyle ();
+    double2double_fun value2slider, slider2value;
 
   public:
 
     int delay;
 
-    Adjuster (Glib::ustring vlabel, double vmin, double vmax, double vstep, double vdefault, Gtk::Image *imgIcon=NULL);
+    Adjuster (Glib::ustring vlabel, double vmin, double vmax, double vstep, double vdefault, Gtk::Image *imgIcon=NULL, double2double_fun slider2value=NULL, double2double_fun value2slider=NULL);
     virtual ~Adjuster ();
 
     // Add an "Automatic" checkbox next to the reset button.

rtgui/whitebalance.cc

@@ -24,6 +24,7 @@
 
 #define MINTEMP 1500   //1200
 #define MAXTEMP 60000  //12000
+#define CENTERTEMP 4750
 #define MINGREEN 0.02
 #define MAXGREEN 5.0
 #define MINEQUAL 0.8
@@ -61,6 +62,59 @@ void WhiteBalance::cleanup () {
     }
 }
 
+static double wbSlider2Temp(double sval) {
+
+    // slider range: 0 - 10000
+    double temp;
+    if (sval <= 5000) {
+        // linear below center-temp
+        temp = MINTEMP + (sval / 5000.0) * (CENTERTEMP - MINTEMP);
+    } else {
+        const double slope = (double)(CENTERTEMP - MINTEMP) / (MAXTEMP - CENTERTEMP);
+        double x = (sval - 5000) / 5000; // x 0..1
+        double y = x * slope + (1.0 - slope)*pow(x, 4.0);
+        //double y = pow(x, 4.0);
+        temp = CENTERTEMP + y * (MAXTEMP - CENTERTEMP);
+    }
+    if (temp < MINTEMP) temp = MINTEMP;
+    if (temp > MAXTEMP) temp = MAXTEMP;
+    return temp;
+}
+
+static double wbTemp2Slider(double temp) {
+
+    double sval;
+    if (temp <= CENTERTEMP) {
+        sval = ((temp - MINTEMP) / (CENTERTEMP - MINTEMP)) * 5000.0;
+    } else {
+        const double slope = (double)(CENTERTEMP - MINTEMP) / (MAXTEMP - CENTERTEMP);
+        const double y = (temp - CENTERTEMP) / (MAXTEMP - CENTERTEMP);
+        double x = pow(y, 0.25); // rough guess of x, will be a little lower
+        double y1;
+        double k = 0.1;
+        bool add = true;
+        // the y=f(x) function is a mess to invert, therefore we have this trial-refinement loop instead.
+        // from tests, worst case is about 20 iterations, ie no problem
+        for (;;) {
+            y1 = x * slope + (1.0 - slope)*pow(x, 4.0);
+            if (5000 * fabs(y1 - y) < 0.1) break;
+            if (y1 < y) {
+                if (!add) k /= 2;
+                x += k;
+                add = true;
+            } else {
+                if (add) k /= 2;
+                x -= k;
+                add = false;
+            }
+        }
+        sval = 5000.0 + x * 5000.0;
+    }
+    if (sval < 0) sval = 0;
+    if (sval > 10000) sval = 10000;
+    return sval;
+}
+
 WhiteBalance::WhiteBalance () : Gtk::VBox(), FoldableToolPanel(this), wbp(NULL), wblistener(NULL) {
 
   set_border_width(4);
@@ -181,7 +235,7 @@ WhiteBalance::WhiteBalance () : Gtk::VBox(), FoldableToolPanel(this), wbp(NULL),
 
   pack_start (*spotbox, Gtk::PACK_SHRINK, 4);
 
-  temp = Gtk::manage (new Adjuster (M("TP_WBALANCE_TEMPERATURE"), MINTEMP, MAXTEMP, 5, 4750));
+  temp = Gtk::manage (new Adjuster (M("TP_WBALANCE_TEMPERATURE"), MINTEMP, MAXTEMP, 5, CENTERTEMP, NULL, &wbSlider2Temp, &wbTemp2Slider));
   green = Gtk::manage (new Adjuster (M("TP_WBALANCE_GREEN"), MINGREEN, MAXGREEN, 0.001, 1.0));
   equal = Gtk::manage (new Adjuster (M("TP_WBALANCE_EQBLUERED"), MINEQUAL, MAXEQUAL, 0.001, 1.0));
   cache_customTemp (0);