Experimental Drivers UI Tweak: Use icons for variable types

This commit aims to streamline the driver variables layout a bit
* Each variable type now has an icon. (The loc diff and rot diff ones are placeholders,
  which could deserve something better/dedicated if we continue to use this)
* Instead of taking up an entire row, the variable type dropdown now only shows
  an icon, and is located before the variable name field.

Feedback wanted: Is this more/less confusing than it was?

2 files changed, 26 insertions, 16 deletions

diff --git a/source/blender/editors/space_graph/graph_buttons.c b/source/blender/editors/space_graph/graph_buttons.c
index 8230ba27db2..a9ab1502e16 100644
--- a/source/blender/editors/space_graph/graph_buttons.c
+++ b/source/blender/editors/space_graph/graph_buttons.c
@@ -851,21 +851,34 @@ static void graph_panel_drivers(const bContext *C, Panel *pa)
 	for (dvar = driver->variables.first; dvar; dvar = dvar->next) {
 		PointerRNA dvar_ptr;
 		uiLayout *box, *row;
+		uiLayout *subrow, *sub;
 		
 		/* sub-layout column for this variable's settings */
 		col = uiLayoutColumn(pa->layout, true);
 		
-		/* header panel */
+		/* 1) header panel */
 		box = uiLayoutBox(col);
-		/* first row context info for driver */
 		RNA_pointer_create(ale->id, &RNA_DriverVariable, dvar, &dvar_ptr);
 		
 		row = uiLayoutRow(box, false);
 		block = uiLayoutGetBlock(row);
-		/* variable name */
-		uiItemR(row, &dvar_ptr, "name", 0, "", ICON_NONE);
 		
-		/* invalid name? */
+		/* 1.1) variable type and name */
+		subrow = uiLayoutRow(row, true);
+		
+		/* 1.1.1) variable type */
+		sub = uiLayoutRow(subrow, true);                     /* HACK: special group just for the enum, otherwise we */
+		uiLayoutSetAlignment(sub, UI_LAYOUT_ALIGN_LEFT);  /*       we get ugly layout with text included too...  */
+		
+		uiItemR(sub, &dvar_ptr, "type", UI_ITEM_R_ICON_ONLY, "", ICON_NONE);
+		
+		/* 1.1.2) variable name */
+		sub = uiLayoutRow(subrow, true);                       /* HACK: special group to counteract the effects of the previous */
+		uiLayoutSetAlignment(sub, UI_LAYOUT_ALIGN_EXPAND);  /*       enum, which now pushes everything too far right         */
+		
+		uiItemR(sub, &dvar_ptr, "name", 0, "", ICON_NONE);
+		
+		/* 1.2) invalid name? */
 		UI_block_emboss_set(block, UI_EMBOSS_NONE);
 		
 		if (dvar->flag & DVAR_FLAG_INVALID_NAME) {
@@ -874,17 +887,14 @@ static void graph_panel_drivers(const bContext *C, Panel *pa)
 			UI_but_func_set(but, driver_dvar_invalid_name_query_cb, dvar, NULL); // XXX: reports?
 		}
 		
-		/* remove button */
+		/* 1.3) remove button */
 		but = uiDefIconBut(block, UI_BTYPE_BUT, B_IPO_DEPCHANGE, ICON_X, 290, 0, UI_UNIT_X, UI_UNIT_Y,
 		                   NULL, 0.0, 0.0, 0.0, 0.0, IFACE_("Delete target variable"));
 		UI_but_func_set(but, driver_delete_var_cb, driver, dvar);
 		UI_block_emboss_set(block, UI_EMBOSS);
 		
-		/* variable type */
-		row = uiLayoutRow(box, false);
-		uiItemR(row, &dvar_ptr, "type", 0, "", ICON_NONE);
-				
-		/* variable type settings */
+		
+		/* 2) variable type settings */
 		box = uiLayoutBox(col);
 		/* controls to draw depends on the type of variable */
 		switch (dvar->type) {
@@ -902,7 +912,7 @@ static void graph_panel_drivers(const bContext *C, Panel *pa)
 				break;
 		}
 		
-		/* value of variable */
+		/* 3) value of variable */
 		if (driver->flag & DRIVER_FLAG_SHOWDEBUG) {
 			char valBuf[32];
 			
diff --git a/source/blender/makesrna/intern/rna_fcurve.c b/source/blender/makesrna/intern/rna_fcurve.c
index 32008640930..a6e6f0713d7 100644
--- a/source/blender/makesrna/intern/rna_fcurve.c
+++ b/source/blender/makesrna/intern/rna_fcurve.c
@@ -1467,11 +1467,11 @@ static void rna_def_drivervar(BlenderRNA *brna)
 	PropertyRNA *prop;
 	
 	static EnumPropertyItem prop_type_items[] = {
-		{DVAR_TYPE_SINGLE_PROP, "SINGLE_PROP", 0, "Single Property", "Use the value from some RNA property (Default)"},
-		{DVAR_TYPE_TRANSFORM_CHAN, "TRANSFORMS", 0, "Transform Channel",
+		{DVAR_TYPE_SINGLE_PROP, "SINGLE_PROP", ICON_RNA, "Single Property", "Use the value from some RNA property (Default)"},
+		{DVAR_TYPE_TRANSFORM_CHAN, "TRANSFORMS", ICON_MANIPUL, "Transform Channel",
 		                           "Final transformation value of object or bone"},
-		{DVAR_TYPE_ROT_DIFF, "ROTATION_DIFF", 0, "Rotational Difference", "Use the angle between two bones"},
-		{DVAR_TYPE_LOC_DIFF, "LOC_DIFF", 0, "Distance", "Distance between two bones or objects"},
+		{DVAR_TYPE_ROT_DIFF, "ROTATION_DIFF", ICON_PARTICLE_TIP, "Rotational Difference", "Use the angle between two bones"},  /* XXX: Icon... */
+		{DVAR_TYPE_LOC_DIFF, "LOC_DIFF", ICON_FULLSCREEN_ENTER, "Distance", "Distance between two bones or objects"},          /* XXX: Icon... */
 		{0, NULL, 0, NULL, NULL}
 	};