[Bf-blender-cvs] SVN commit: /data/svn/bf-blender [37286] trunk/blender/source/blender/ editors/interface/interface.c: smarter precision calculation, so 0. 000001 isn't displayed as 0.00.

[Campbell Barton]

Revision: 37286
          http://projects.blender.org/scm/viewvc.php?view=rev&root=bf-blender&revision=37286
Author:   campbellbarton
Date:     2011-06-07 04:06:10 +0000 (Tue, 07 Jun 2011)
Log Message:
-----------
smarter precision calculation, so 0.000001 isn't displayed as 0.00.
there is a minor problem with this commit:
 0.00001 --> 0.00001 # good
 0.000015 --> 0.000015 # good
 0.0000199 --> 0.00002 # ok
 0.00002 --> 0.000020 # wrong, has trailing 0

Tried to fix this but the case is hard to check for without more calculations which Id like to avoid. 

Modified Paths:
--------------
    trunk/blender/source/blender/editors/interface/interface.c

Modified: trunk/blender/source/blender/editors/interface/interface.c
===================================================================
--- trunk/blender/source/blender/editors/interface/interface.c	2011-06-07 02:39:40 UTC (rev 37285)
+++ trunk/blender/source/blender/editors/interface/interface.c	2011-06-07 04:06:10 UTC (rev 37286)
@@ -449,11 +449,36 @@
 
 /* link line drawing is not part of buttons or theme.. so we stick with it here */
 
-static int ui_but_float_precision(uiBut *but, double UNUSED(value))
+static int ui_but_float_precision(uiBut *but, double value)
 {
-	int prec= (int)but->a2;
-	if(prec==0) prec= (but->hardmax < 10.001f) ? 3 : 2;
-	else CLAMP(prec, 1, 7);
+	int prec;
+
+	/* first check if prec is 0 and fallback to a simple default */
+	if((prec= (int)but->a2) == 0) {
+		prec= (but->hardmax < 10.001f) ? 3 : 2;
+	}
+
+	/* check on the number of decimal places neede to display
+	 * the number, this is so 0.00001 is not displayed as 0.00,
+	 * _but_, this is only for small values si 10.0001 will not get
+	 * the same treatment */
+	if(value != 0.0 && (value= ABS(value)) < 0.1) {
+		double prec_d= -(log10(value));
+		double prec_d_floor = floor(prec_d + FLT_EPSILON);
+		int test_prec= (int)prec_d_floor;
+
+		/* this check is so 0.00016 from isnt rounded to 0.0001 _but_ it is not working ideally because 0.0002 becomes 0.00020 */
+		if(prec_d - prec_d_floor > FLT_EPSILON) {
+			test_prec += 2;
+		}
+
+		if(test_prec > prec && test_prec <= 7) {
+			prec= test_prec;
+		}
+	}
+
+	CLAMP(prec, 1, 7);
+
 	return prec;
 }