From 2e08c9164a91f8eb04a8a306b371dc4bb2cc5a40 Mon Sep 17 00:00:00 2001 From: Ell Date: Mon, 16 Jul 2018 00:57:41 -0400 Subject: [PATCH] Issue #1850 - Undoing the "straighten" operation in the Measure tool ... ... does not restore the measure points Halt the measure tool after straightening, thus removing the expectation that undoing the operation should restore the original points. Halting the tool, rather than making undo work "as expected", sidesteps several issues: - Implementing undo correctly is tricky, since image-undo and tool-undo are handled separately. - In fact, the measure tool doesn't provide tool-undo, so that image edits can be undone while the tool is active without affecting the tool, and it's not clear that we want to change this behavior. However, this makes undoing a straighten operation a special case, and it's not entirely clear what the behavior should be when undoing other kinds of transformations, or when the measure points had changed since the straighten operation. - Perhaps most importantly, measure tool points are restricted to the pixel grid, which means that when measuring an angle against an orientation that's not fully horizontal or vertical in image space (either using a 3-point angle, or when the canvas is rotated), the resulting transformed point after straightening doesn't generally land on the pixel grid, causing it to be rounded, which can result in a non-zero angle after the rotation. This is especially ugly, since clicking "straighten" again at this point would cause another non- trivial rotation. --- app/tools/gimpmeasuretool.c | 21 +-------------------- 1 file changed, 1 insertion(+), 20 deletions(-) diff --git a/app/tools/gimpmeasuretool.c b/app/tools/gimpmeasuretool.c index 4788ae477a..c498aced13 100644 --- a/app/tools/gimpmeasuretool.c +++ b/app/tools/gimpmeasuretool.c @@ -852,24 +852,5 @@ gimp_measure_tool_straighten_button_clicked (GtkWidget *button, GimpTransformTool *tr_tool = GIMP_TRANSFORM_TOOL (measure); if (gimp_transform_tool_transform (tr_tool, tool->display)) - { - gdouble x0, y0; - gdouble x1, y1; - - gimp_matrix3_transform_point (&tr_tool->transform, - measure->x[0], - measure->y[0], - &x0, &y0); - gimp_matrix3_transform_point (&tr_tool->transform, - measure->x[1], - measure->y[1], - &x1, &y1); - - g_object_set (measure->widget, - "x1", SIGNED_ROUND (x0), - "y1", SIGNED_ROUND (y0), - "x2", SIGNED_ROUND (x1), - "y2", SIGNED_ROUND (y1), - NULL); - } + gimp_tool_control (tool, GIMP_TOOL_ACTION_HALT, tool->display); }