Fix T58549, T56741: HSV color picker issues with Filmic view transform.

In 2d655d3 the color picker was changed to use display space HSV values.
This works ok for a simple sRGB EOTF, but fails with view transforms like
Filmic where display space V 1.0 maps to RGB 16.292.

Instead we now use the color_picking role from the OCIO config when
converting from RGB to HSV in the color picker. This role is set to sRGB
in the default OCIO config.

This color space fits the following requirements:

* It is approximately perceptually linear, so that the HSV numbers and
  the HSV cube/circle have an intuitive distribution.
* It has the same gamut as the scene linear color space.
* Color picking values 0..1 map to scene linear values in the 0..1 range,
  so that picked albedo values are energy conserving.

1 files changed, 36 insertions, 52 deletions

diff --git a/source/blender/editors/interface/interface_widgets.c b/source/blender/editors/interface/interface_widgets.c
index f9a96803661..fd34ac8f140 100644
--- a/source/blender/editors/interface/interface_widgets.c
+++ b/source/blender/editors/interface/interface_widgets.c
@@ -2581,23 +2581,16 @@ static void ui_draw_but_HSVCIRCLE(uiBut *but, uiWidgetColors *wcol, const rcti *
 	float radius = (float)min_ii(BLI_rcti_size_x(rect), BLI_rcti_size_y(rect)) / 2.0f;
 
 	ColorPicker *cpicker = but->custom_data;
-	const float *hsv_ptr = cpicker->color_data;
-	float rgb[3], hsvo[3], hsv[3], col[3], colcent[3];
-	bool color_profile = ui_but_is_colorpicker_display_space(but);
+	float rgb[3], hsv[3], rgb_center[3];
+	bool is_color_gamma = ui_but_is_color_gamma(but);
 
-	/* color */
-	ui_but_v3_get(but, rgb);
-
-	/* since we use compat functions on both 'hsv' and 'hsvo', they need to be initialized */
-	hsvo[0] = hsv[0] = hsv_ptr[0];
-	hsvo[1] = hsv[1] = hsv_ptr[1];
-	hsvo[2] = hsv[2] = hsv_ptr[2];
-
-	if (color_profile)
-		ui_block_cm_to_display_space_v3(but->block, rgb);
+	/* Initialize for compatibility. */
+	copy_v3_v3(hsv, cpicker->color_data);
 
+	/* Compute current hue. */
+	ui_but_v3_get(but, rgb);
+	ui_scene_linear_to_color_picker_space(but, rgb);
 	ui_rgb_to_color_picker_compat_v(rgb, hsv);
-	copy_v3_v3(hsvo, hsv);
 
 	CLAMP(hsv[2], 0.0f, 1.0f); /* for display only */
 
@@ -2611,7 +2604,13 @@ static void ui_draw_but_HSVCIRCLE(uiBut *but, uiWidgetColors *wcol, const rcti *
 			hsv[2] = 0.5f;
 	}
 
-	ui_color_picker_to_rgb(0.0f, 0.0f, hsv[2], colcent, colcent + 1, colcent + 2);
+	const float hsv_center[3] = {0.0f, 0.0f, hsv[2]};
+	ui_color_picker_to_rgb_v(hsv_center, rgb_center);
+	ui_scene_linear_to_color_picker_space(but, rgb_center);
+
+	if (!is_color_gamma) {
+		ui_block_cm_to_display_space_v3(but->block, rgb_center);
+	}
 
 	GPUVertFormat *format = immVertexFormat();
 	uint pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
@@ -2620,19 +2619,27 @@ static void ui_draw_but_HSVCIRCLE(uiBut *but, uiWidgetColors *wcol, const rcti *
 	immBindBuiltinProgram(GPU_SHADER_2D_SMOOTH_COLOR);
 
 	immBegin(GPU_PRIM_TRI_FAN, tot + 2);
-	immAttr3fv(color, colcent);
+	immAttr3fv(color, rgb_center);
 	immVertex2f(pos, centx, centy);
 
 	float ang = 0.0f;
 	for (int a = 0; a <= tot; a++, ang += radstep) {
 		float si = sinf(ang);
 		float co = cosf(ang);
+		float hsv_ang[3];
+		float rgb_ang[3];
 
-		ui_hsvcircle_vals_from_pos(hsv, hsv + 1, rect, centx + co * radius, centy + si * radius);
+		ui_hsvcircle_vals_from_pos(hsv_ang, hsv_ang + 1, rect, centx + co * radius, centy + si * radius);
+		hsv_ang[2] = hsv[2];
 
-		ui_color_picker_to_rgb_v(hsv, col);
+		ui_color_picker_to_rgb_v(hsv_ang, rgb_ang);
+		ui_color_picker_to_scene_linear_space(but, rgb_ang);
 
-		immAttr3fv(color, col);
+		if (!is_color_gamma) {
+			ui_block_cm_to_display_space_v3(but->block, rgb_ang);
+		}
+
+		immAttr3fv(color, rgb_ang);
 		immVertex2f(pos, centx + co * radius, centy + si * radius);
 	}
 	immEnd();
@@ -2656,8 +2663,13 @@ static void ui_draw_but_HSVCIRCLE(uiBut *but, uiWidgetColors *wcol, const rcti *
 	GPU_line_smooth(false);
 
 	/* cursor */
+	copy_v3_v3(hsv, cpicker->color_data);
+	ui_but_v3_get(but, rgb);
+	ui_scene_linear_to_color_picker_space(but, rgb);
+	ui_rgb_to_color_picker_compat_v(rgb, hsv);
+
 	float xpos, ypos;
-	ui_hsvcircle_pos_from_vals(but, rect, hsvo, &xpos, &ypos);
+	ui_hsvcircle_pos_from_vals(but, rect, hsv, &xpos, &ypos);
 	ui_hsv_cursor(xpos, ypos);
 }
 
@@ -2812,18 +2824,6 @@ void ui_draw_gradient(const rcti *rect, const float hsv[3], const int type, cons
 	immUnbindProgram();
 }
 
-bool ui_but_is_colorpicker_display_space(uiBut *but)
-{
-	bool color_profile = but->block->color_profile;
-
-	if (but->rnaprop) {
-		if (RNA_property_subtype(but->rnaprop) == PROP_COLOR_GAMMA)
-			color_profile = false;
-	}
-
-	return color_profile;
-}
-
 void ui_hsvcube_pos_from_vals(uiBut *but, const rcti *rect, float *hsv, float *xp, float *yp)
 {
 	float x = 0.0f, y = 0.0f;
@@ -2865,15 +2865,12 @@ static void ui_draw_but_HSVCUBE(uiBut *but, const rcti *rect)
 	ColorPicker *cpicker = but->custom_data;
 	float *hsv = cpicker->color_data;
 	float hsv_n[3];
-	bool use_display_colorspace = ui_but_is_colorpicker_display_space(but);
 
+	/* Initialize for compatibility. */
 	copy_v3_v3(hsv_n, hsv);
 
 	ui_but_v3_get(but, rgb);
-
-	if (use_display_colorspace)
-		ui_block_cm_to_display_space_v3(but->block, rgb);
-
+	ui_scene_linear_to_color_picker_space(but, rgb);
 	rgb_to_hsv_compat_v(rgb, hsv_n);
 
 	ui_draw_gradient(rect, hsv_n, but->a1, 1.0f);
@@ -2901,15 +2898,9 @@ static void ui_draw_but_HSV_v(uiBut *but, const rcti *rect)
 	const float rad = wcol->roundness * BLI_rcti_size_x(rect);
 	float x, y;
 	float rgb[3], hsv[3], v;
-	bool color_profile = but->block->color_profile;
-
-	if (but->rnaprop && RNA_property_subtype(but->rnaprop) == PROP_COLOR_GAMMA)
-		color_profile = false;
 
 	ui_but_v3_get(but, rgb);
-
-	if (color_profile)
-		ui_block_cm_to_display_space_v3(but->block, rgb);
+	ui_scene_linear_to_color_picker_space(but, rgb);
 
 	if (but->a1 == UI_GRAD_L_ALT)
 		rgb_to_hsl_v(rgb, hsv);
@@ -2920,9 +2911,6 @@ static void ui_draw_but_HSV_v(uiBut *but, const rcti *rect)
 	/* map v from property range to [0,1] */
 	if (but->a1 == UI_GRAD_V_ALT) {
 		float min = but->softmin, max = but->softmax;
-		if (color_profile) {
-			ui_block_cm_to_display_space_range(but->block, &min, &max);
-		}
 		v = (v - min) / (max - min);
 	}
 
@@ -3378,16 +3366,12 @@ static void widget_swatch(uiBut *but, uiWidgetColors *wcol, rcti *rect, int stat
 {
 	uiWidgetBase wtb;
 	float rad, col[4];
-	bool color_profile = but->block->color_profile;
 
 	col[3] = 1.0f;
 
 	if (but->rnaprop) {
 		BLI_assert(but->rnaindex == -1);
 
-		if (RNA_property_subtype(but->rnaprop) == PROP_COLOR_GAMMA)
-			color_profile = false;
-
 		if (RNA_property_array_length(&but->rnapoin, but->rnaprop) == 4) {
 			col[3] = RNA_property_float_get_index(&but->rnapoin, but->rnaprop, 3);
 		}
@@ -3415,7 +3399,7 @@ static void widget_swatch(uiBut *but, uiWidgetColors *wcol, rcti *rect, int stat
 		round_box_edges(&wtb, roundboxalign, rect, rad);
 	}
 
-	if (color_profile)
+	if (!ui_but_is_color_gamma(but))
 		ui_block_cm_to_display_space_v3(but->block, col);
 
 	rgba_float_to_uchar((unsigned char *)wcol->inner, col);