Sequencer: bright/contrast modifier

Behaves in exactly the same way as bright/contrast compositor node.

Some code could be de-duplicated, like contrast formula and mask
influence, but wouldn't call it stopper for commit since it's
already needed for grading Mango.

release/scripts/startup/bl_ui/space_sequencer.py

@@ -930,6 +930,10 @@ class SEQUENCER_PT_modifiers(SequencerButtonsPanel, Panel):
                     box.template_curve_mapping(mod, "curve_mapping", type='COLOR')
                 elif mod.type == 'HUE_CORRECT':
                     box.template_curve_mapping(mod, "curve_mapping", type='HUE')
+                elif mod.type == 'BRIGHT_CONTRAST':
+                    col = box.column()
+                    col.prop(mod, "bright")
+                    col.prop(mod, "contrast")
 
 
 if __name__ == "__main__":  # only for live edit.

source/blender/blenkernel/intern/seqmodifier.c

@@ -394,6 +394,106 @@ static SequenceModifierTypeInfo seqModifier_HueCorrect = {
 	hue_correct_apply                 /* apply */
 };
 
+/* **** Bright/Contrast Modifier **** */
+
+typedef struct BrightContrastThreadData {
+	float bright;
+	float contrast;
+} BrightContrastThreadData;
+
+void brightcontrast_apply_threaded(int width, int height, unsigned char *rect, float *rect_float,
+                                   unsigned char *mask_rect, float *mask_rect_float, void *data_v)
+{
+	BrightContrastThreadData *data = (BrightContrastThreadData *) data_v;
+	int x, y;
+
+	float i;
+	int c;
+	float a, b, v;
+	float brightness = data->bright / 100.0f;
+	float contrast = data->contrast;
+	float delta = contrast / 200.0f;
+
+	a = 1.0f - delta * 2.0f;
+	/*
+	 * The algorithm is by Werner D. Streidt
+	 * (http://visca.com/ffactory/archives/5-99/msg00021.html)
+	 * Extracted of OpenCV demhist.c
+	 */
+	if (contrast > 0) {
+		a = 1.0f / a;
+		b = a * (brightness - delta);
+	}
+	else {
+		delta *= -1;
+		b = a * (brightness + delta);
+	}
+
+	for (y = 0; y < height; y++) {
+		for (x = 0; x < width; x++) {
+			int pixel_index = (y * width + x) * 4;
+
+			if (rect) {
+				unsigned char *pixel = rect + pixel_index;
+
+				for (c = 0; c < 3; c++) {
+					i = pixel[c];
+					v = a * i + b;
+
+					if (mask_rect) {
+						unsigned char *m = mask_rect + pixel_index;
+						float t = (float) m[c] / 255.0f;
+
+						pixel[c] = pixel[c] * (1.0f - t) + v * t;
+					}
+					else
+						pixel[c] = v;
+				}
+			}
+			else if (rect_float) {
+				float *pixel = rect_float + pixel_index;
+
+				for (c = 0; c < 3; c++) {
+					i = pixel[c];
+					v = a * i + b;
+
+					if (mask_rect_float) {
+						float *m = mask_rect_float + pixel_index;
+
+						pixel[c] = pixel[c] * (1.0f - m[c]) + v * m[c];
+					}
+					else
+						pixel[c] = v;
+				}
+			}
+		}
+	}
+}
+
+ImBuf *brightcontrast_apply(struct SequenceModifierData *smd, ImBuf *ibuf, ImBuf *mask)
+{
+	BrightContrastModifierData *bcmd = (BrightContrastModifierData *) smd;
+	BrightContrastThreadData data;
+	ImBuf *ibuf_new = IMB_dupImBuf(ibuf);
+
+	data.bright = bcmd->bright;
+	data.contrast = bcmd->contrast;
+
+	modifier_apply_threaded(ibuf_new, mask, brightcontrast_apply_threaded, &data);
+
+	return ibuf_new;
+}
+
+static SequenceModifierTypeInfo seqModifier_BrightContrast = {
+	"Bright/Contrast",                   /* name */
+	"BrightContrastModifierData",        /* struct_name */
+	sizeof(BrightContrastModifierData),  /* struct_size */
+	NULL,                                /* init_data */
+	NULL,                                /* free_data */
+	NULL,                                /* copy_data */
+	brightcontrast_apply                 /* apply */
+};
+
 /*********************** Modifier functions *************************/
 
 static void sequence_modifier_type_info_init(void)
@@ -403,6 +503,7 @@ static void sequence_modifier_type_info_init(void)
 	INIT_TYPE(ColorBalance);
 	INIT_TYPE(Curves);
 	INIT_TYPE(HueCorrect);
+	INIT_TYPE(BrightContrast);
 
 #undef INIT_TYPE
 }

source/blender/makesdna/DNA_sequence_types.h

@@ -271,6 +271,13 @@ typedef struct HueCorrectModifierData {
 	struct CurveMapping curve_mapping;
 } HueCorrectModifierData;
 
+typedef struct BrightContrastModifierData {
+	SequenceModifierData modifier;
+
+	float bright;
+	float contrast;
+} BrightContrastModifierData;
+
 #define MAXSEQ          32
 
 #define SELECT 1
@@ -401,6 +408,7 @@ enum {
 	seqModifierType_ColorBalance   = 1,
 	seqModifierType_Curves         = 2,
 	seqModifierType_HueCorrect     = 3,
+	seqModifierType_BrightContrast = 4,
 
 	NUM_SEQUENCE_MODIFIER_TYPES
 };

source/blender/makesrna/intern/rna_sequencer.c

@@ -63,6 +63,7 @@ EnumPropertyItem sequence_modifier_type_items[] = {
 	{seqModifierType_ColorBalance, "COLOR_BALANCE", ICON_NONE, "Color Balance", ""},
 	{seqModifierType_Curves, "CURVES", ICON_NONE, "Curves", ""},
 	{seqModifierType_HueCorrect, "HUE_CORRECT", ICON_NONE, "Hue Correct", ""},
+	{seqModifierType_BrightContrast, "BRIGHT_CONTRAST", ICON_NONE, "Bright/Contrast", ""},
 	{0, NULL, 0, NULL, NULL}
 };
 
@@ -918,6 +919,8 @@ static StructRNA *rna_SequenceModifier_refine(struct PointerRNA *ptr)
 			return &RNA_CurvesModifier;
 		case seqModifierType_HueCorrect:
 			return &RNA_HueCorrectModifier;
+		case seqModifierType_BrightContrast:
+			return &RNA_BrightContrastModifier;
 		default:
 			return &RNA_SequenceModifier;
 	}
@@ -2340,12 +2343,34 @@ static void rna_def_hue_modifier(BlenderRNA *brna)
 	RNA_def_property_update(prop, NC_SCENE | ND_SEQUENCER, "rna_SequenceModifier_update");
 }
 
+static void rna_def_brightcontrast_modifier(BlenderRNA *brna)
+{
+	StructRNA *srna;
+	PropertyRNA *prop;
+
+	srna = RNA_def_struct(brna, "BrightContrastModifier", "SequenceModifier");
+	RNA_def_struct_sdna(srna, "BrightContrastModifierData");
+	RNA_def_struct_ui_text(srna, "BrightContrastModifier", "Bright/contrast modifier data for sequence strip");
+
+	prop = RNA_def_property(srna, "bright", PROP_FLOAT, PROP_UNSIGNED);
+	RNA_def_property_float_sdna(prop, NULL, "bright");
+	RNA_def_property_ui_text(prop, "Bright", "");
+	RNA_def_property_update(prop, NC_SCENE | ND_SEQUENCER, "rna_SequenceModifier_update");
+
+	prop = RNA_def_property(srna, "contrast", PROP_FLOAT, PROP_UNSIGNED);
+	RNA_def_property_float_sdna(prop, NULL, "contrast");
+	RNA_def_property_ui_text(prop, "Contrast", "");
+	RNA_def_property_update(prop, NC_SCENE | ND_SEQUENCER, "rna_SequenceModifier_update");
+}
+
 static void rna_def_modifiers(BlenderRNA *brna)
 {
 	rna_def_modifier(brna);
+
 	rna_def_colorbalance_modifier(brna);
 	rna_def_curves_modifier(brna);
 	rna_def_hue_modifier(brna);
+	rna_def_brightcontrast_modifier(brna);
 }
 
 void RNA_def_sequencer(BlenderRNA *brna)