Skip to content

filmic rgb: scale the graphs to fit target white above 100% #22667

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
nicknezis wants to merge 2 commits into
base: master
Choose a base branch
from
Open

filmic rgb: scale the graphs to fit target white above 100% #22667

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
2424f6f
filmic rgb: scale the graphs to fit target white above 100%
claude Oct 17, 2026
614e5f1
RELEASE_NOTES.md: filmic rgb graphs above 100% target white
claude Oct 17, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions RELEASE_NOTES.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -604,6 +604,10 @@ changes (where available).
lighttable, and when importing images with a new camera maker, model or
lens.

- Fixed the filmic rgb graphs cutting off the curve when target white
is above 100% for HDR output: the look and mapping views now scale
their y axis to fit the curve and mark 100% display.

## Lua

### API Version
Expand Down
54 changes: 42 additions & 12 deletions src/iop/filmicrgb.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3435,6 +3435,16 @@ static gboolean dt_iop_tonecurve_draw(GtkWidget *widget, cairo_t *crf, dt_iop_mo
const float grey = p->grey_point_source / 100.f;
const float DR = p->white_point_source - p->black_point_source;

// a target white above 100% puts the end of the curve above y = 1,
// so the y axis is stretched to y_top and y = 1 is y_height pixels high
const float spline_top = fmaxf(1.f, g->spline.y[4]);
float y_top = spline_top;
if(g->gui_mode == DT_FILMIC_GUI_BASECURVE)
y_top = powf(spline_top, p->output_power);
else if(g->gui_mode == DT_FILMIC_GUI_BASECURVE_LOG)
y_top = dt_log_scale_axis(powf(spline_top, p->output_power), LOGBASE);
const float y_height = g->graph_height / y_top;

// set the graph as the origin of the coordinates
cairo_translate(cr, margin_left, margin_top);

Expand Down Expand Up @@ -3493,16 +3503,23 @@ static gboolean dt_iop_tonecurve_draw(GtkWidget *widget, cairo_t *crf, dt_iop_mo
cairo_translate(cr, 0., -g->graph_height);

if(g->gui_mode == DT_FILMIC_GUI_LOOK || g->gui_mode == DT_FILMIC_GUI_BASECURVE)
dt_draw_grid(cr, 4, 0, 0, g->graph_width, g->graph_height);
dt_draw_grid(cr, 4, 0, 0, g->graph_width, y_height);
else if(g->gui_mode == DT_FILMIC_GUI_BASECURVE_LOG)
dt_draw_loglog_grid(cr, 4, 0, 0, g->graph_width, g->graph_height, LOGBASE);
dt_draw_loglog_grid(cr, 4, 0, 0, g->graph_width, y_height, LOGBASE);

// mark 100% display when the graph extends above it
if(y_top > 1.f)
{
dt_draw_line(cr, 0, y_height, g->graph_width, y_height);
cairo_stroke(cr);
}

// reset coordinates
cairo_restore(cr);

// draw identity line
cairo_move_to(cr, 0, g->graph_height);
cairo_line_to(cr, g->graph_width, 0);
cairo_line_to(cr, g->graph_width, g->graph_height - y_height);
cairo_stroke(cr);

cairo_set_line_width(cr, DT_PIXEL_APPLY_DPI(2.));
Expand Down Expand Up @@ -3571,7 +3588,7 @@ static gboolean dt_iop_tonecurve_draw(GtkWidget *widget, cairo_t *crf, dt_iop_mo
else if(g->gui_mode == DT_FILMIC_GUI_BASECURVE_LOG)
y_start = dt_log_scale_axis(powf(y_start, p->output_power), LOGBASE);

cairo_move_to(cr, 0, g->graph_height * (1.0 - y_start));
cairo_move_to(cr, 0, g->graph_height - y_start * y_height);

for(int k = 1; k < 256; k++)
{
Expand All @@ -3597,7 +3614,7 @@ static gboolean dt_iop_tonecurve_draw(GtkWidget *widget, cairo_t *crf, dt_iop_mo
const float margin = 1E-5;
if(y > g->spline.y[4] + margin)
{
y = fminf(y, 1.0f);
y = fminf(y, spline_top);
cairo_set_source_rgb(cr, 0.75, .5, 0.);
}
else if(y < g->spline.y[0] - margin)
Expand All @@ -3615,9 +3632,9 @@ static gboolean dt_iop_tonecurve_draw(GtkWidget *widget, cairo_t *crf, dt_iop_mo
else if(g->gui_mode == DT_FILMIC_GUI_BASECURVE_LOG)
y = dt_log_scale_axis(powf(y, p->output_power), LOGBASE);

cairo_line_to(cr, x * g->graph_width, g->graph_height * (1.0 - y));
cairo_line_to(cr, x * g->graph_width, g->graph_height - y * y_height);
cairo_stroke(cr);
cairo_move_to(cr, x * g->graph_width, g->graph_height * (1.0 - y));
cairo_move_to(cr, x * g->graph_width, g->graph_height - y * y_height);
}

cairo_restore(cr);
Expand All @@ -3644,7 +3661,7 @@ static gboolean dt_iop_tonecurve_draw(GtkWidget *widget, cairo_t *crf, dt_iop_mo
}

cairo_set_source_rgb(cr, 0.75, 0.5, 0.0);
cairo_arc(cr, x_grey * g->graph_width, (1.0 - y_grey) * g->graph_height, DT_PIXEL_APPLY_DPI(6), 0,
cairo_arc(cr, x_grey * g->graph_width, g->graph_height - y_grey * y_height, DT_PIXEL_APPLY_DPI(6), 0,
2. * M_PI);
cairo_fill(cr);
cairo_stroke(cr);
Expand Down Expand Up @@ -3715,7 +3732,7 @@ static gboolean dt_iop_tonecurve_draw(GtkWidget *widget, cairo_t *crf, dt_iop_mo
if(red) cairo_set_source_rgb(cr, 0.8, 0.35, 0.35);

// draw bullet
cairo_arc(cr, x * g->graph_width, (1.0 - y) * g->graph_height, DT_PIXEL_APPLY_DPI(4), start_angle, end_angle);
cairo_arc(cr, x * g->graph_width, g->graph_height - y * y_height, DT_PIXEL_APPLY_DPI(4), start_angle, end_angle);
cairo_fill(cr);
cairo_stroke(cr);

Expand All @@ -3736,7 +3753,7 @@ static gboolean dt_iop_tonecurve_draw(GtkWidget *widget, cairo_t *crf, dt_iop_mo
pango_layout_set_text(layout, text, -1);
pango_layout_get_pixel_extents(layout, &g->ink, NULL);
cairo_move_to(cr, -2. * g->inset - g->ink.width - g->ink.x,
(1.0 - y_grey) * g->graph_height - 0.5 * g->ink.height - g->ink.y);
g->graph_height - y_grey * y_height - 0.5 * g->ink.height - g->ink.y);
pango_cairo_show_layout(cr, layout);
cairo_stroke(cr);

Expand All @@ -3759,7 +3776,7 @@ static gboolean dt_iop_tonecurve_draw(GtkWidget *widget, cairo_t *crf, dt_iop_mo
pango_layout_set_text(layout, text, -1);
pango_layout_get_pixel_extents(layout, &g->ink, NULL);
cairo_move_to(cr, -2. * g->inset - g->ink.width - g->ink.x,
(1.0 - y_black) * g->graph_height - 0.5 * g->ink.height - g->ink.y);
g->graph_height - y_black * y_height - 0.5 * g->ink.height - g->ink.y);
pango_cairo_show_layout(cr, layout);
cairo_stroke(cr);

Expand All @@ -3769,10 +3786,23 @@ static gboolean dt_iop_tonecurve_draw(GtkWidget *widget, cairo_t *crf, dt_iop_mo
pango_layout_set_text(layout, text, -1);
pango_layout_get_pixel_extents(layout, &g->ink, NULL);
cairo_move_to(cr, -2. * g->inset - g->ink.width - g->ink.x,
(1.0 - y_white) * g->graph_height - 0.5 * g->ink.height - g->ink.y);
g->graph_height - y_white * y_height - 0.5 * g->ink.height - g->ink.y);
pango_cairo_show_layout(cr, layout);
cairo_stroke(cr);

// mark the y axis graduation at 100% display, unless the white label already sits there
if(y_top > 1.f && (y_white - 1.f) * y_height > 1.5f * g->line_height)
{
set_color(cr, darktable.bauhaus->graph_fg);
snprintf(text, sizeof(text), "%.0f", 100.f);
pango_layout_set_text(layout, text, -1);
pango_layout_get_pixel_extents(layout, &g->ink, NULL);
cairo_move_to(cr, -2. * g->inset - g->ink.width - g->ink.x,
g->graph_height - y_height - 0.5 * g->ink.height - g->ink.y);
pango_cairo_show_layout(cr, layout);
cairo_stroke(cr);
}

// mark the x axis graduation at black spot
set_color(cr, darktable.bauhaus->graph_fg);
if(g->gui_mode == DT_FILMIC_GUI_LOOK)
Expand Down
Loading