Fix issues with float precision in numinput, like 'R 123' who would show additional 'noise' digits.

Expose float precision helper in UI_interface.h API, so that numinput can use this helper as numbuttons already do.

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D186

4 files changed, 70 insertions, 55 deletions

diff --git a/source/blender/editors/include/UI_interface.h b/source/blender/editors/include/UI_interface.h
index 735e7f35d61..10a4b383694 100644
--- a/source/blender/editors/include/UI_interface.h
+++ b/source/blender/editors/include/UI_interface.h
@@ -941,4 +941,9 @@ void UI_template_fix_linking(void);
 bool UI_editsource_enable_check(void);
 void UI_editsource_active_but_test(uiBut *but);
 
+/* Float precision helpers */
+#define UI_PRECISION_FLOAT_MAX 7
+
+int uiFloatPrecisionCalc(int prec, double value);
+
 #endif  /* __UI_INTERFACE_H__ */
diff --git a/source/blender/editors/interface/interface.c b/source/blender/editors/interface/interface.c
index e6e175284d0..24924564ab4 100644
--- a/source/blender/editors/interface/interface.c
+++ b/source/blender/editors/interface/interface.c
@@ -78,9 +78,6 @@
 
 #include "interface_intern.h"
 
-#define PRECISION_FLOAT_MAX 7
-#define PRECISION_FLOAT_MAX_POW 10000000 /* pow(10, PRECISION_FLOAT_MAX)  */
-
 /* avoid unneeded calls to ui_get_but_val */
 #define UI_BUT_VALUE_UNSET DBL_MAX
 #define UI_GET_BUT_VALUE_INIT(_but, _value) if (_value == DBL_MAX) {  (_value) = ui_get_but_val(_but); } (void)0
@@ -432,67 +429,21 @@ void uiExplicitBoundsBlock(uiBlock *block, int minx, int miny, int maxx, int max
 	block->bounds_type = UI_BLOCK_BOUNDS_NONE;
 }
 
-/* ************** LINK LINE DRAWING  ************* */
-
-/* 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 value)
 {
 	int prec;
-	const double pow10_neg[PRECISION_FLOAT_MAX + 1] = {1.0, 0.1, 0.01, 0.001, 0.0001, 0.00001, 0.000001, 0.0000001};
 
 	/* first check if prec is 0 and fallback to a simple default */
 	if ((prec = (int)but->a2) == -1) {
 		prec = (but->hardmax < 10.001f) ? 3 : 2;
 	}
 
-	BLI_assert(prec <= PRECISION_FLOAT_MAX);
-	BLI_assert(pow10_neg[prec] == pow(10, -prec));
-
-	/* check on the number of decimal places need 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 */
-	value = ABS(value);
-	if ((value < pow10_neg[prec]) &&
-	    (value > (1.0 / PRECISION_FLOAT_MAX_POW)))
-	{
-		int value_i = (int)((value * PRECISION_FLOAT_MAX_POW) + 0.5);
-		if (value_i != 0) {
-			const int prec_span = 3; /* show: 0.01001, 5 would allow 0.0100001 for eg. */
-			int test_prec;
-			int prec_min = -1;
-			int dec_flag = 0;
-			int i = PRECISION_FLOAT_MAX;
-			while (i && value_i) {
-				if (value_i % 10) {
-					dec_flag |= 1 << i;
-					prec_min = i;
-				}
-				value_i /= 10;
-				i--;
-			}
-
-			/* even though its a small value, if the second last digit is not 0, use it */
-			test_prec = prec_min;
-
-			dec_flag = (dec_flag >> (prec_min + 1)) & ((1 << prec_span) - 1);
-
-			while (dec_flag) {
-				test_prec++;
-				dec_flag = dec_flag >> 1;
-			}
-
-			if (test_prec > prec) {
-				prec = test_prec;
-			}
-		}
-	}
+	return uiFloatPrecisionCalc(prec, value);
+}
 
-	CLAMP(prec, 0, PRECISION_FLOAT_MAX);
+/* ************** LINK LINE DRAWING  ************* */
 
-	return prec;
-}
+/* link line drawing is not part of buttons or theme.. so we stick with it here */
 
 static void ui_draw_linkline(uiLinkLine *line, int highlightActiveLines)
 {
@@ -1803,7 +1754,7 @@ static void ui_get_but_string_unit(uiBut *but, char *str, int len_max, double va
 	if (float_precision == -1) {
 		/* Sanity checks */
 		precision = (int)but->a2;
-		if      (precision > PRECISION_FLOAT_MAX) precision = PRECISION_FLOAT_MAX;
+		if      (precision > UI_PRECISION_FLOAT_MAX) precision = UI_PRECISION_FLOAT_MAX;
 		else if (precision == -1)                 precision = 2;
 	}
 	else {
diff --git a/source/blender/editors/interface/interface_utils.c b/source/blender/editors/interface/interface_utils.c
index e1f39b1d556..812eb9345ac 100644
--- a/source/blender/editors/interface/interface_utils.c
+++ b/source/blender/editors/interface/interface_utils.c
@@ -36,6 +36,7 @@
 #include "DNA_object_types.h"
 
 #include "BLI_utildefines.h"
+#include "BLI_math.h"
 #include "BLI_string.h"
 
 #include "BLF_translation.h"
@@ -224,3 +225,58 @@ int uiIconFromID(ID *id)
 
 	return (ptr.type) ? RNA_struct_ui_icon(ptr.type) : ICON_NONE;
 }
+
+/********************************** Misc **************************************/
+
+/**
+ * Returns the best "UI" precision for given floating value, so that e.g. 10.000001 rather gets drawn as '10'...
+ */
+int uiFloatPrecisionCalc(int prec, double value)
+{
+	static const double pow10_neg[UI_PRECISION_FLOAT_MAX + 1] = {1e0, 1e-1, 1e-2, 1e-3, 1e-4, 1e-5, 1e-6, 1e-7};
+	static const double max_pow = 10000000.0;  /* pow(10, UI_PRECISION_FLOAT_MAX) */
+
+	BLI_assert(prec <= UI_PRECISION_FLOAT_MAX);
+	BLI_assert(pow10_neg[prec] == pow(10, -prec));
+
+	/* check on the number of decimal places need 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.
+	 */
+	value = ABS(value);
+	if ((value < pow10_neg[prec]) && (value > (1.0 / max_pow))) {
+		int value_i = (int)((value * max_pow) + 0.5);
+		if (value_i != 0) {
+			const int prec_span = 3; /* show: 0.01001, 5 would allow 0.0100001 for eg. */
+			int test_prec;
+			int prec_min = -1;
+			int dec_flag = 0;
+			int i = UI_PRECISION_FLOAT_MAX;
+			while (i && value_i) {
+				if (value_i % 10) {
+					dec_flag |= 1 << i;
+					prec_min = i;
+				}
+				value_i /= 10;
+				i--;
+			}
+
+			/* even though its a small value, if the second last digit is not 0, use it */
+			test_prec = prec_min;
+
+			dec_flag = (dec_flag >> (prec_min + 1)) & ((1 << prec_span) - 1);
+
+			while (dec_flag) {
+				test_prec++;
+				dec_flag = dec_flag >> 1;
+			}
+
+			if (test_prec > prec) {
+				prec = test_prec;
+			}
+		}
+	}
+
+	CLAMP(prec, 0, UI_PRECISION_FLOAT_MAX);
+
+	return prec;
+}
diff --git a/source/blender/editors/util/numinput.c b/source/blender/editors/util/numinput.c
index 2828973e91d..b9459d57f26 100644
--- a/source/blender/editors/util/numinput.c
+++ b/source/blender/editors/util/numinput.c
@@ -45,6 +45,7 @@
 #endif
 
 #include "ED_numinput.h"
+#include "UI_interface.h"
 
 
 /* NumInput.val_flag[] */
@@ -80,13 +81,15 @@ void outputNumInput(NumInput *n, char *str)
 {
 	short i, j;
 	const int ln = NUM_STR_REP_LEN;
-	const int prec = 4; /* draw-only, and avoids too much issues with radian->degrees conversion. */
+	int prec = 2; /* draw-only, and avoids too much issues with radian->degrees conversion. */
 
 	for (j = 0; j <= n->idx_max; j++) {
 		/* if AFFECTALL and no number typed and cursor not on number, use first number */
 		i = (n->flag & NUM_AFFECT_ALL && n->idx != j && !(n->val_flag[j] & NUM_EDITED)) ? 0 : j;
 
 		if (n->val_flag[i] & NUM_EDITED) {
+			/* Get the best precision, allows us to draw '10.0001' as '10' instead! */
+			prec = uiFloatPrecisionCalc(prec, (double)n->val[i]);
 			if (i == n->idx) {
 				const char *heading_exp = "", *trailing_exp = "";
 				char before_cursor[NUM_STR_REP_LEN];