Font textbox overflow: Different methods

Sometimes the text doesn't fit. What to do in this case?

* Overflow: The default behaviour still is to overflow the text.
* Truncated: If any text box is defined we can also not draw the text
  that goes outside the text boxes.
* Scale to Fit: For single-text box texts we can scale down the text until
  it fits.

To support textboxes we are bisecting the scale until we find a good
match. Right now the hardcoded iteration limit is 20, and the threshold 0.0001f.

An alternative in the future would be to tackle this by integrating existing
layout engines such as HarfBuzz.

Note: Scale to fit won't work for multiple text-boxes if any of them has
either width or height as zero.

Reviewers: campbellbarton
Differential Revision: https://developer.blender.org/D3874

Feature development sponsored by Viddyoze.

1 files changed, 15 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_curve.c b/source/blender/makesrna/intern/rna_curve.c
index e9671754288..41849f3efe7 100644
--- a/source/blender/makesrna/intern/rna_curve.c
+++ b/source/blender/makesrna/intern/rna_curve.c
@@ -974,6 +974,13 @@ static void rna_def_font(BlenderRNA *UNUSED(brna), StructRNA *srna)
 		{0, NULL, 0, NULL, NULL}
 	};
 
+	static const EnumPropertyItem prop_overflow_items[] = {
+		{CU_OVERFLOW_NONE, "NONE", 0, "Overflow", "Let the text overflow outside the text boxes"},
+		{CU_OVERFLOW_SCALE, "SCALE", 0, "Scale to Fit", "Scale down the text to fit inside the text boxes"},
+		{CU_OVERFLOW_TRUNCATE, "TRUNCATE", 0, "Truncate", "Truncate the text that would go outside the text boxes"},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	/* Enums */
 	prop = RNA_def_property(srna, "align_x", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "spacemode");
@@ -987,6 +994,14 @@ static void rna_def_font(BlenderRNA *UNUSED(brna), StructRNA *srna)
 	RNA_def_property_ui_text(prop, "Text Vertical Align", "Text vertical align from the object center");
 	RNA_def_property_update(prop, 0, "rna_Curve_update_data");
 
+	prop = RNA_def_property(srna, "overflow", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "overflow");
+	RNA_def_property_enum_items(prop, prop_overflow_items);
+	RNA_def_property_enum_default(prop, CU_OVERFLOW_NONE);
+	RNA_def_property_ui_text(prop, "Textbox Overflow",
+	                         "Handle the text behaviour when it doesn't fit in the text boxes");
+	RNA_def_property_update(prop, 0, "rna_Curve_update_data");
+
 	/* number values */
 	prop = RNA_def_property(srna, "size", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "fsize");