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+---- Thread: Gimp 3.0 - How to draw stuff with python scripts (pixel by pixel) (/Thread-Gimp-3-0-How-to-draw-stuff-with-python-scripts-pixel-by-pixel)
Gimp 3.0 - How to draw stuff with python scripts (pixel by pixel) - krokots - 03-04-2026
I need help writing some basic script that will draw, for example, a circle, or a rectangle of randomly colored pixels, at a specified X and Y on the selected layer. For now I got this :
Code:
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import gi
gi.require_version("Gimp", "3.0")
gi.require_version("GimpUi", "3.0")
gi.require_version("Gegl", "0.4")
from gi.repository import Gimp, GimpUi, Gegl, GObject, GLib
import sys
class DrawCirclePlugin(Gimp.PlugIn):
def do_set_i18n(self, name):
return False
def do_query_procedures(self):
return ["python-fu-draw-circle"]
def do_create_procedure(self, name):
Gegl.init(None)
procedure = Gimp.ImageProcedure.new(
self, name,
Gimp.PDBProcType.PLUGIN,
self.run,
None,
)
procedure.set_image_types("*")
procedure.set_sensitivity_mask(Gimp.ProcedureSensitivityMask.DRAWABLE)
procedure.set_menu_label("Draw Circle")
procedure.add_menu_path("<Image>/Filters/Draw")
procedure.set_documentation(
"Draw a filled/outlined circle of a chosen color and radius",
"Draws a circle centred at (center_x, center_y) with the given "
"radius, fill color, and optional stroke outline.",
name,
)
procedure.set_attribution("Your Name", "Your Name", "2024")
procedure.add_int_argument(
"center-x", "Center X", "X coordinate of the circle center (px)",
0, GLib.MAXINT, 100, GObject.ParamFlags.READWRITE,
)
procedure.add_int_argument(
"center-y", "Center Y", "Y coordinate of the circle center (px)",
0, GLib.MAXINT, 100, GObject.ParamFlags.READWRITE,
)
procedure.add_int_argument(
"radius", "Radius", "Radius of the circle in pixels",
1, GLib.MAXINT, 50, GObject.ParamFlags.READWRITE,
)
default_color = Gegl.Color.new("red")
procedure.add_color_argument(
"color", "Fill Color", "Color used to fill (and stroke) the circle",
True, default_color, GObject.ParamFlags.READWRITE,
)
procedure.add_boolean_argument(
"fill", "Fill circle", "Fill the interior of the circle",
True, GObject.ParamFlags.READWRITE,
)
procedure.add_boolean_argument(
"stroke", "Draw outline", "Stroke an outline around the circle",
False, GObject.ParamFlags.READWRITE,
)
procedure.add_int_argument(
"stroke-width", "Outline width", "Outline thickness in pixels",
1, 500, 2, GObject.ParamFlags.READWRITE,
)
return procedure
def run(self, procedure, run_mode, image, drawables, config, run_data):
Gimp.message("A")
if run_mode == Gimp.RunMode.INTERACTIVE:
GimpUi.init("draw_circle")
dialog = GimpUi.ProcedureDialog.new(procedure, config, "Draw Circle")
dialog.fill(None)
if not dialog.run():
dialog.destroy()
return procedure.new_return_values(
Gimp.PDBStatusType.CANCEL, GLib.Error()
)
dialog.destroy()
drawable = drawables[0]
image.undo_group_start()
# draw stuff here
image.undo_group_end()
return procedure.new_return_values(Gimp.PDBStatusType.SUCCESS, GLib.Error())
Gimp.main(DrawCirclePlugin.__gtype__, sys.argv)I see that Drawable class have a method SetPixel, but in the docs it says that undo doesn't work on that. So, how to modify drawable pixels so that undo works ?
RE: Gimp 3.0 - How to draw stuff with python scripts (pixel by pixel) - programmer_ceds - 03-05-2026
[attachment=14289][attachment=14290]
(03-04-2026, 05:15 PM)krokots Wrote: I see that Drawable class have a method SetPixel, but in the docs it says that undo doesn't work on that. So, how to modify drawable pixels so that undo works ?
The attached scripts are in Script-fu but would be easily convertible to Python - they draw a filled circle and a hollow circle by filling or stroking a selection (an ellipse with the foci at the same position. For drawing other shapes it would probably be best to define paths and then stroke them. Alternatively define a selection and stroke that. Avoid using set_pixel()
RE: Gimp 3.0 - How to draw stuff with python scripts (pixel by pixel) - krokots - 03-06-2026
I see that the scripts use selection as a way to paint pixels. But what if I wanted to paint something else, for example, a diagonal line ? From X1, Y1 to X2, Y2 ?
RE: Gimp 3.0 - How to draw stuff with python scripts (pixel by pixel) - MrsP-from-C - 03-07-2026
Maybe these help you?
https://developer.gimp.org/api/3.0/libgimp/func.paintbrush.html
https://developer.gimp.org/api/3.0/libgimp/func.paintbrush_default.html
Basically you define which brush to use, define its settings and define start and end point.
RE: Gimp 3.0 - How to draw stuff with python scripts (pixel by pixel) - krokots - 03-07-2026
That is a really nice suggestion! That could work for drawing straight lines. BUT...what I really want to achieve, is a mix of things. I want to create a script that creates "random" pixelated trees. For this, I also would like to be able to modify pixels on a canvas.
So, for example, I create a circle, fill it with a color (or use a gradient). Nice - that I can do in python. But for next thing - I need to modify slightly some random pixels in the filled circle (to create a noise-like texture).
That would need some kind of function for changing pixels on the active layer.
