dt_masks_overlay_transform_t Struct Reference

How the overlay maps image coordinates onto its cairo target. More...

#include <masks_gui.h>

Collaboration diagram for dt_masks_overlay_transform_t:

Data Fields
double	scale
double	offset_x
double	offset_y

Detailed Description

How the overlay maps image coordinates onto its cairo target.

The darkroom passes NULL and the mapping comes from the viewport – zoom, pan, and the GUI's device pixel ratio. None of that exists outside the GUI: dt_gui_get_global() is darktable.gui, which is NULL in ansel-cli and in the test binaries, so the viewport path would dereference it. A headless caller supplies its own mapping instead, which is also what a regression test wants – a fixed, reproducible transform rather than whatever the window happened to be showing.

This exists so the OVERLAY IS DRAWN BY THE SAME CODE in both cases. The alternative – a second drawing path for diagnostics – would be a fork that stops agreeing with the GUI exactly when it is needed to explain a GUI problem.

Definition at line 597 of file masks_gui.h.

Field Documentation

offset_x

double dt_masks_overlay_transform_t::offset_x

Definition at line 600 of file masks_gui.h.

offset_y

double dt_masks_overlay_transform_t::offset_y

target-space translation, applied before the scale

Definition at line 600 of file masks_gui.h.

scale

double dt_masks_overlay_transform_t::scale

image pixels -> target pixels

Definition at line 599 of file masks_gui.h.

Referenced by _check_hidpi_placement(), _overlay_leftovers(), _time_overlay_form(), and dt_masks_debug_write_png().

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The documentation for this struct was generated from the following file:

• masks_gui.h