Initial push

README.md

@@ -1,3 +1,15 @@
-# PixelBash
+`# PixelBash
 
-a GTK + Python simple paint application.
+A simple GTK + Python based paint application.
+
+# Keyboard Shortcuts
+* (undo) ctrl+z
+* (redo) ctrl+y
+* (save as) ctrl+s
+* (new surface) ctrl+n
+
+# Images
+![1 Default view starting out. ](images/pic1.png)
+![2 Blank canvas. ](images/pic2.png)
+![3 Blank canvas being edited. ](images/pic3.png)
+![4 Image being edited. ](images/pic4.png)

requirements.txt

@@ -0,0 +1,4 @@
+PyGObject==3.40.1
+pycairo==1.28.0
+pygobject-stubs --no-cache-dir --config-settings=config=Gtk3,Gdk3,Soup2
+setproctitle==1.2.2

src/__builtins__.py

@@ -0,0 +1,37 @@
+# Python imports
+import builtins
+import threading
+
+# Lib imports
+
+# Application imports
+from libs.event_system import EventSystem
+
+
+# NOTE: Threads WILL NOT die with parent's destruction.
+def threaded_wrapper(fn):
+    def wrapper(*args, **kwargs):
+        thread = threading.Thread(target = fn, args = args, kwargs = kwargs, daemon = False)
+        thread.start()
+        return thread
+    return wrapper
+
+# NOTE: Threads WILL die with parent's destruction.
+def daemon_threaded_wrapper(fn):
+    def wrapper(*args, **kwargs):
+        thread = threading.Thread(target = fn, args = args, kwargs = kwargs, daemon = True)
+        thread.start()
+        return thread
+    return wrapper
+
+
+# NOTE: Just reminding myself we can add to builtins two different ways...
+# __builtins__.update({"event_system": Builtins()})
+builtins.APP_NAME          = "PixelBash"
+
+builtins.threaded          = threaded_wrapper
+builtins.daemon_threaded   = daemon_threaded_wrapper
+builtins.get_class         = lambda x: globals()[x]
+
+builtins.event_system      = EventSystem()
+

src/__main__.py

@@ -0,0 +1,33 @@
+#!/usr/bin/python3
+
+# Python imports
+import argparse
+import faulthandler
+import traceback
+from setproctitle import setproctitle
+
+import tracemalloc
+tracemalloc.start()
+
+# Lib imports
+
+# Application imports
+from __builtins__ import *
+from app import Application
+
+
+
+def main():
+    setproctitle(f"{APP_NAME}")
+    faulthandler.enable()
+
+    app = Application()
+    app.run()
+
+
+if __name__ == '__main__':
+    try:
+        main()
+    except Exception as e:
+        traceback.print_exc()
+        quit()

src/app.py

@@ -0,0 +1,16 @@
+# Python imports
+
+# Lib imports
+
+# Application imports
+from window import Window
+
+
+class Application:
+    def __init__(self):
+        super(Application, self).__init__()
+
+
+    def run(self):
+        win = Window()
+        win.start()

src/data/cbindings/ctypes_cdll_example_not_working/compile.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+# . CONFIG.sh
+
+# set -o xtrace       ## To debug scripts
+# set -o errexit      ## To exit on error
+# set -o errunset     ## To exit if a variable is referenced but not set
+
+function main() {
+    cd "$(dirname "")"
+    echo "Working Dir: " $(pwd)
+
+    gcc -shared -o pixels_to_cairo_surface.so -fPIC pixels_to_cairo_surface.c
+}
+main "$@";

src/data/cbindings/ctypes_cdll_example_not_working/example.py

@@ -0,0 +1,71 @@
+# Python imports
+import ctypes
+
+# Lib imports
+import cairo
+import gi
+
+gi.require_version('Gtk', '3.0')
+
+from gi.repository import Gtk
+
+# Application imports
+
+
+
+def _pixels_to_cairo_surface(
+    pixbuf: GdkPixbuf.Pixbuf,
+    width: int,
+    height: int
+) -> cairo.ImageSurface:
+    rowstride    = pixbuf.get_rowstride()
+    has_alpha    = pixbuf.get_has_alpha()
+    n_channels   = pixbuf.get_n_channels()
+    pixels       = memoryview(pixbuf.get_pixels())
+
+    cairo_stride = width * 4
+    cairo_data   = bytearray(height * cairo_stride)
+
+    lib          = ctypes.cdll.LoadLibrary(".pixels_to_cairo_surface.so")
+    IntArray     = ctypes.c_int * len(pixels)
+    pixel_buffer = IntArray(*pixels)
+    lib.pixels_to_cairo_surface.restype  = ctypes.POINTER(ctypes.c_uint * (height * cairo_stride))
+    lib.pixels_to_cairo_surface.argtypes = [
+        ctypes.c_int,
+        ctypes.c_bool,
+        ctypes.c_int,
+        ctypes.c_int,
+        ctypes.c_int,
+        ctypes.POINTER(ctypes.c_int)
+    ]
+
+    _cairo_data = lib.pixels_to_cairo_surface(
+        rowstride,
+        has_alpha,
+        n_channels,
+        width,
+        height,
+        pixel_buffer
+    )
+
+    cairo_data = _cairo_data.contents
+
+    return cairo.ImageSurface.create_for_data(
+        cairo_data,
+        cairo.FORMAT_ARGB32,
+        width,
+        height,
+        cairo_stride
+    )
+
+
+def main():
+    img_path = ""
+    pixbuf   = Gtk.Image.new_from_file(img_path).get_pixbuf()
+    width    = pixbuf.get_width()
+    height   = pixbuf.get_height()
+    _pixels_to_cairo_surface(pixbuf, width, height)
+
+
+if __name__ == "__main__":
+    main()

src/data/cbindings/ctypes_cdll_example_not_working/pixels_to_cairo_surface.c

@@ -0,0 +1,38 @@
+#include <stdlib.h>
+
+unsigned int *pixels_to_cairo_surface(
+    const int rowstride,
+    const bool has_alpha,
+    const int n_channels,
+    const int width,
+    const int height,
+    const int* pixels
+) {
+    int cairo_stride         = width * 4;
+    unsigned int* cairo_data = malloc(sizeof(unsigned int) * height * cairo_stride);
+
+    for (int y = 0; y < height; y++) {
+        for (int x = 0; x < width; x++) {
+            int p_offset = y * rowstride + x * n_channels;
+            int c_offset = y * cairo_stride + x * 4;
+
+            int r = pixels[p_offset];
+            int g = pixels[p_offset + 1];
+            int b = pixels[p_offset + 2];
+            int a = (has_alpha) ? pixels[p_offset + 3] : 255;
+
+            // Premultiply alpha (important for correct rendering in Cairo)
+            int r_premul = (r * a) / 255;
+            int g_premul = (g * a) / 255;
+            int b_premul = (b * a) / 255;
+
+            // Cairo expects data in BGRA (ARGB32 native endianness)
+            cairo_data[c_offset + 0] = b_premul;
+            cairo_data[c_offset + 1] = g_premul;
+            cairo_data[c_offset + 2] = r_premul;
+            cairo_data[c_offset + 3] = a;
+        }
+    }
+
+    return cairo_data;
+}

src/data/cbindings/pixbuf2cairo.py

@@ -0,0 +1,9 @@
+def __bootstrap__():
+    global __bootstrap__, __loader__, __file__
+    import sys, pkg_resources, importlib.util
+    __file__ = pkg_resources.resource_filename(__name__, 'pixbuf2cairo.cpython-313-x86_64-linux-gnu.so')
+    __loader__ = None; del __bootstrap__, __loader__
+    spec = importlib.util.spec_from_file_location(__name__,__file__)
+    mod = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(mod)
+__bootstrap__()

src/data/cbindings/python_package_works/compile.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+# . CONFIG.sh
+
+# set -o xtrace       ## To debug scripts
+# set -o errexit      ## To exit on error
+# set -o errunset     ## To exit if a variable is referenced but not set
+
+function main() {
+    cd "$(dirname "")"
+    echo "Working Dir: " $(pwd)
+
+    python3 setup.py build && python3 setup.py install --user
+}
+main "$@";

src/data/cbindings/python_package_works/pixbuf2cairo.c

@@ -0,0 +1,80 @@
+#include <Python.h>
+#include <cairo.h>
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#include <stdlib.h>
+
+static PyObject* pixbuf_to_cairo_data(PyObject* self, PyObject* args) {
+    PyObject *py_pixbuf;
+
+    if (!PyArg_ParseTuple(args, "O", &py_pixbuf)) {
+        return NULL;
+    }
+
+    GdkPixbuf *pixbuf = (GdkPixbuf *) PyLong_AsVoidPtr(py_pixbuf);
+    if (!GDK_IS_PIXBUF(pixbuf)) {
+        PyErr_SetString(PyExc_TypeError, "Invalid GdkPixbuf pointer.");
+        return NULL;
+    }
+
+    int width              = gdk_pixbuf_get_width(pixbuf);
+    int height             = gdk_pixbuf_get_height(pixbuf);
+    int rowstride          = gdk_pixbuf_get_rowstride(pixbuf);
+    int n_channels         = gdk_pixbuf_get_n_channels(pixbuf);
+    gboolean has_alpha     = gdk_pixbuf_get_has_alpha(pixbuf);
+    const guchar *pixels   = gdk_pixbuf_get_pixels(pixbuf);
+
+    int cairo_stride       = cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, width);
+    Py_ssize_t buffer_size = height * cairo_stride;
+
+    guchar *cairo_data = malloc(buffer_size);
+    if (!cairo_data) {
+        PyErr_NoMemory();
+        return NULL;
+    }
+
+    for (int y = 0; y < height; ++y) {
+        const guchar *src = pixels + y * rowstride;
+        guchar *dst = cairo_data + y * cairo_stride;
+
+        for (int x = 0; x < width; ++x) {
+            const guchar *p = src + x * n_channels;
+            guchar *q = dst + x * 4;
+
+            guchar r = p[0];
+            guchar g = p[1];
+            guchar b = p[2];
+            guchar a = 255;
+
+            if (has_alpha) {
+                a = p[3];
+                r = (r * a) / 255;
+                g = (g * a) / 255;
+                b = (b * a) / 255;
+            }
+
+            q[0] = b;
+            q[1] = g;
+            q[2] = r;
+            q[3] = a;
+        }
+    }
+
+    return PyBytes_FromStringAndSize((const char *) cairo_data, buffer_size);
+}
+
+static PyMethodDef Methods[] = {
+    {"pixbuf_to_cairo_data", pixbuf_to_cairo_data, METH_VARARGS, "Convert GdkPixbuf* to compatible Cairo ImageSurface data format."},
+    {NULL, NULL, 0, NULL}
+};
+
+static struct PyModuleDef moduledef = {
+    PyModuleDef_HEAD_INIT,
+    "pixbuf2cairo",
+    NULL,
+    -1,
+    Methods
+};
+
+PyMODINIT_FUNC PyInit_pixbuf2cairo(void) {
+    return PyModule_Create(&moduledef);
+}

src/data/cbindings/python_package_works/setup.py

@@ -0,0 +1,31 @@
+from setuptools import setup, Extension
+import gi
+gi.require_version("GdkPixbuf", "2.0")
+
+from gi.repository import GdkPixbuf
+from gi.repository import GObject
+
+pkg_config_args = [
+    "--cflags", "--libs",
+    "gdk-pixbuf-2.0",
+    "cairo"
+]
+
+from subprocess import check_output
+
+def get_pkgconfig_flags(flag_type):
+    return check_output(["pkg-config", flag_type] + pkg_config_args).decode().split()
+
+ext = Extension(
+    "pixbuf2cairo",
+    sources=["pixbuf2cairo.c"],
+    include_dirs=[],
+    extra_compile_args=get_pkgconfig_flags("--cflags"),
+    extra_link_args=get_pkgconfig_flags("--libs")
+)
+
+setup(
+    name="pixbuf2cairo",
+    version="0.1",
+    ext_modules=[ext]
+)

src/data/event.py

@@ -0,0 +1,11 @@
+# Python imports
+
+# Lib imports
+import cairo
+
+# Application imports
+
+
+class Event:
+    def __init__(self):
+        super(Event, self).__init__()

src/data/mouse_buttons.py

@@ -0,0 +1,11 @@
+# Python imports
+
+# Lib imports
+
+# Application imports
+
+
+class MouseButton:
+    LEFT_BUTTON   = 1
+    MIDDLE_BUTTON = 2
+    RIGHT_BUTTON  = 3

src/data/point.py

@@ -0,0 +1,13 @@
+# Python imports
+
+# Lib imports
+
+# Application imports
+
+
+class Point:
+    def __init__(self, x = 0, y = 0):
+        super(Point, self).__init__()
+
+        self.x: int = x
+        self.y: int = y

src/data/points.py

@@ -0,0 +1,10 @@
+# Python imports
+
+# Lib imports
+
+# Application imports
+
+
+class Points(list):
+    def __init__(self):
+        super(Points, self).__init__()

src/libs/event_collection.py

@@ -0,0 +1,10 @@
+# Python imports
+
+# Lib imports
+
+# Application imports
+
+
+class EventCollection(list):
+    def __init__(self):
+        super(EventCollection, self).__init__()

src/libs/event_system.py

@@ -0,0 +1,73 @@
+# Python imports
+from collections import defaultdict
+
+# Lib imports
+
+# Application imports
+from .singleton import Singleton
+
+
+
+class EventSystem(Singleton):
+    """ Create event system. """
+
+    def __init__(self):
+        self.subscribers = defaultdict(list)
+        self._is_paused  = False
+
+        self._subscribe_to_events()
+
+
+    def _subscribe_to_events(self):
+        self.subscribe("pause_event_processing", self._pause_processing_events)
+        self.subscribe("resume_event_processing", self._resume_processing_events)
+
+    def _pause_processing_events(self):
+        self._is_paused = True
+
+    def _resume_processing_events(self):
+        self._is_paused = False
+
+    def subscribe(self, event_type, fn):
+        self.subscribers[event_type].append(fn)
+
+    def unsubscribe(self, event_type, fn):
+        self.subscribers[event_type].remove(fn)
+
+    def unsubscribe_all(self, event_type):
+        self.subscribers.pop(event_type, None)
+
+    def emit(self, event_type, data = None):
+        if self._is_paused and event_type != "resume_event_processing":
+            return
+
+        if event_type in self.subscribers:
+            for fn in self.subscribers[event_type]:
+                if data:
+                    if hasattr(data, '__iter__') and not type(data) is str:
+                        fn(*data)
+                    else:
+                        fn(data)
+                else:
+                    fn()
+
+    def emit_and_await(self, event_type, data = None):
+        if self._is_paused and event_type != "resume_event_processing":
+            return
+
+        """ NOTE: Should be used when signal has only one listener and vis-a-vis """
+        if event_type in self.subscribers:
+            response = None
+            for fn in self.subscribers[event_type]:
+                if data:
+                    if hasattr(data, '__iter__') and not type(data) is str:
+                        response = fn(*data)
+                    else:
+                        response = fn(data)
+                else:
+                    response = fn()
+
+                if not response in (None, ''):
+                    break
+
+            return response

src/libs/history_manager.py

@@ -0,0 +1,10 @@
+# Python imports
+
+# Lib imports
+
+# Application imports
+
+
+class HistoryManager(list):
+    def __init__(self):
+        super(HistoryManager, self).__init__()

src/libs/singleton.py

@@ -0,0 +1,24 @@
+# Python imports
+
+# Lib imports
+
+# Application imports
+
+
+
+class SingletonError(Exception):
+    pass
+
+
+
+class Singleton:
+    ccount = 0
+
+    def __new__(cls, *args, **kwargs):
+        obj        = super(Singleton, cls).__new__(cls)
+        cls.ccount += 1
+
+        if cls.ccount == 2:
+            raise SingletonError(f"Exceeded {cls.__name__} instantiation limit...")
+
+        return obj

src/libs/surface_manager.py

@@ -0,0 +1,10 @@
+# Python imports
+
+# Lib imports
+
+# Application imports
+
+
+class SurfaceManager(list):
+    def __init__(self):
+        super(SurfaceManager, self).__init__()

src/widgets/brushes/__init__.py

@@ -0,0 +1,7 @@
+from .brush_base import BrushBase
+from .grid import Grid
+from .arrow import Arrow
+from .line import Line
+from .circle import Circle
+from .square import Square
+from .erase import Erase

src/widgets/brushes/arrow.py

@@ -0,0 +1,45 @@
+# Python imports
+
+# Lib imports
+import cairo
+import traceback
+
+# Application imports
+from data.point import Point
+from data.points import Points
+
+from . import BrushBase
+
+
+class Arrow(BrushBase):
+    def __init__(self):
+        super(Arrow, self).__init__()
+
+        self.points: Points = Points()
+
+    def __copy__(self):
+        copy       = type(self)()
+        copy.color = self.color
+
+        return copy
+
+
+    def update(self, eve = None):
+        if len(self.points) < 2:
+            self.points.append( Point(eve.x, eve.y) )
+            return
+
+        self.points[1] = Point(eve.x, eve.y)
+        self.is_valid = True
+
+
+    def process(self, brush: cairo.Context):
+
+        brush.set_line_width(self.size)
+        brush.set_line_cap(1) # 0 = BUTT, 1 = ROUND, 2 = SQUARE
+        brush.set_source_rgba(*self.color)
+        brush.set_operator(cairo.OPERATOR_OVER);
+
+        brush.move_to(self.points[0].x, self.points[0].y)
+        brush.line_to(self.points[1].x, self.points[1].y)
+        brush.stroke()

src/widgets/brushes/brush_base.py

@@ -0,0 +1,27 @@
+# Python imports
+
+# Lib imports
+import cairo
+
+# Application imports
+from data.event import Event
+
+
+class UnboundException(Exception):
+    ...
+
+
+class BrushBase(Event):
+    def __init__(self):
+        super(BrushBase, self).__init__()
+
+        self.is_valid: bool = False
+        self.size: int      = 12
+        self.color: []      = [0.0, 0.0, 0.0, 1.0]
+
+
+    def update(self, eve):
+        raise UnboundException("Method hasn't been overriden...")
+
+    def process(self, brush: cairo.Context):
+        raise UnboundException("Method hasn't been overriden...")

src/widgets/brushes/circle.py

@@ -0,0 +1,37 @@
+# Python imports
+
+# Lib imports
+import cairo
+
+# Application imports
+from data.point import Point
+from data.points import Points
+
+from . import BrushBase
+
+
+class Circle(BrushBase):
+    def __init__(self):
+        super(Circle, self).__init__()
+
+        self.points: Points = Points()
+
+    def __copy__(self):
+        copy       = type(self)()
+        copy.color = self.color
+
+        return copy
+
+
+    def update(self, eve):
+        self.points.append( Point(eve.x, eve.y) )
+        self.is_valid = True
+
+    def process(self, brush: cairo.Context):
+        brush.set_source_rgba(*self.color)
+        brush.set_operator(cairo.OPERATOR_OVER);
+
+        for point in self.points:
+            brush.move_to(point.x, point.y)
+            brush.arc(point.x, point.y, self.size, 0, 2 * 3.14)
+            brush.fill()

src/widgets/brushes/erase.py

@@ -0,0 +1,42 @@
+# Python imports
+
+# Lib imports
+import cairo
+
+# Application imports
+from data.point import Point
+from data.points import Points
+
+from . import BrushBase
+
+
+class Erase(BrushBase):
+    def __init__(self):
+        super(Erase, self).__init__()
+
+        self.points: Points = Points()
+
+    def __copy__(self):
+        copy       = type(self)()
+        copy.color = self.color
+
+        return copy
+
+
+    def update(self, eve):
+        self.points.append( Point(eve.x, eve.y) )
+        self.is_valid = True
+
+    def process(self, brush: cairo.Context):
+        if len(self.points) < 2: return
+
+        brush.set_line_width(self.size)
+        brush.set_line_cap(1) # 0 = BUTT, 1 = ROUND, 2 = SQUARE
+        brush.set_source_rgba(*self.color)
+        brush.set_operator(cairo.OPERATOR_CLEAR);
+
+        brush.move_to(self.points[0].x, self.points[0].y)
+        for point in self.points[1 : -1]:
+            brush.line_to(point.x, point.y)
+            brush.stroke()
+            brush.move_to(point.x, point.y)

src/widgets/brushes/grid.py

@@ -0,0 +1,46 @@
+# Python imports
+
+# Lib imports
+import cairo
+
+# Application imports
+from . import BrushBase
+
+
+class Grid(BrushBase):
+    def __init__(self):
+        super(Grid, self).__init__()
+
+        self.width        = 800
+        self.height       = 800
+        self.grid_spacing = 12  # px
+        self.color        = [0.2, 0.2, 0.2, 0.64]   # light gray
+
+    def __copy__(self):
+        copy       = type(self)()
+        copy.color = self.color
+
+        return copy
+
+
+    def update(self, eve):
+        self.is_valid = True
+
+    def process(self, brush: cairo.Context):
+        brush.set_source_rgba(*self.color)
+
+        # Draw vertical lines
+        x = 0
+        while x < self.width:
+            brush.move_to(x, 0)
+            brush.line_to(x, self.height)
+            x += self.grid_spacing
+
+        # Draw horizontal lines
+        y = 0
+        while y < self.height:
+            brush.move_to(0, y)
+            brush.line_to(self.width, y)
+            y += self.grid_spacing
+
+        brush.stroke()

src/widgets/brushes/line.py

@@ -0,0 +1,43 @@
+# Python imports
+
+# Lib imports
+import cairo
+import traceback
+
+# Application imports
+from data.point import Point
+from data.points import Points
+
+from . import BrushBase
+
+
+class Line(BrushBase):
+    def __init__(self):
+        super(Line, self).__init__()
+
+        self.points: Points = Points()
+
+    def __copy__(self):
+        copy       = type(self)()
+        copy.color = self.color
+
+        return copy
+
+
+    def update(self, eve = None):
+        self.points.append( Point(eve.x, eve.y) )
+        if len(self.points) < 2: return
+        self.is_valid = True
+
+    def process(self, brush: cairo.Context):
+
+        brush.set_line_width(self.size)
+        brush.set_line_cap(1) # 0 = BUTT, 1 = ROUND, 2 = SQUARE
+        brush.set_source_rgba(*self.color)
+        brush.set_operator(cairo.OPERATOR_OVER);
+
+        brush.move_to(self.points[0].x, self.points[0].y)
+        for point in self.points[1 : -1]:
+            brush.line_to(point.x, point.y)
+            brush.stroke()
+            brush.move_to(point.x, point.y)

src/widgets/brushes/square.py

@@ -0,0 +1,43 @@
+# Python imports
+
+# Lib imports
+import cairo
+
+# Application imports
+from data.point import Point
+from data.points import Points
+
+from . import BrushBase
+
+
+class Square(BrushBase):
+    def __init__(self):
+        super(Square, self).__init__()
+
+        self.points: Points = Points()
+
+    def __copy__(self):
+        copy       = type(self)()
+        copy.color = self.color
+
+        return copy
+
+
+    def update(self, eve):
+        if len(self.points) < 2:
+            self.points.append( Point(eve.x, eve.y) )
+            return
+
+        self.points[1] = Point(eve.x, eve.y)
+        self.is_valid = True
+
+    def process(self, brush: cairo.Context):
+        x1, y1 = self.points[0].x, self.points[0].y
+        x2, y2 = self.points[1].x, self.points[1].y
+        w      = x2 - x1
+        h      = y2 - y1
+
+        brush.set_source_rgba(*self.color)
+        brush.set_operator(cairo.OPERATOR_OVER);
+        brush.rectangle(x1, y1, w, h)
+        brush.fill()

src/widgets/button_box.py

@@ -0,0 +1,103 @@
+# Python imports
+
+# Lib imports
+import gi
+
+gi.require_version('Gtk', '3.0')
+
+from gi.repository import Gtk
+from gi.repository import Gdk
+
+# Application imports
+from .controls.save_as_button import SaveAsButton
+
+
+class ButtonBox(Gtk.Box):
+    def __init__(self):
+        super(ButtonBox, self).__init__()
+
+        self.active_btn = None
+
+        self._setup_styling()
+        self._setup_signals()
+        self._load_widgets()
+
+        self.show_all()
+
+
+    def _setup_styling(self):
+        ...
+
+    def _setup_signals(self):
+        ...
+
+
+    def _load_widgets(self):
+        arrow_btn  = Gtk.ToggleButton(label = "Arrow")
+        line_btn   = Gtk.ToggleButton(label = "Line")
+        circle_btn = Gtk.ToggleButton(label = "Circle")
+        square_btn = Gtk.ToggleButton(label = "Square")
+        erase_btn  = Gtk.ToggleButton(label = "Erase")
+        # save_btn   = Gtk.Button(label = "Save")
+        save_btn   = SaveAsButton()
+        color_btn  = Gtk.ColorButton()
+        size_btn   = Gtk.SpinButton()
+
+        self.active_btn = line_btn
+        line_btn.set_active(True)
+
+        color_btn.set_title("Pick a Color")
+        color_btn.set_use_alpha(True)
+        color_btn.set_rgba( Gdk.RGBA(0.0, 0.0, 0.0, 1.0) )
+
+        size_btn.set_numeric(True)
+        size_btn.set_digits(0)
+        size_btn.set_snap_to_ticks(True)
+        size_btn.set_increments(1.0, 10.0)
+        size_btn.set_range(1.0, 100.0)
+        size_btn.set_value(12.0)
+
+        color_btn.connect("color-set", self.set_brush_color)
+        size_btn.connect("value-changed", self.set_brush_size)
+
+        self.add(arrow_btn)
+        self.add(line_btn)
+        self.add(circle_btn)
+        self.add(square_btn)
+        self.add(color_btn)
+        self.add(size_btn)
+        self.add(erase_btn)
+        self.add(save_btn)
+
+        save_btn.connect("clicked", self.save_image)
+        # Note: For buttons and mapping assignment. Spin and Color bttn will
+        # conveniently throw errors OR not be set regarding get_label and NOT map.
+        for child in self.get_children():
+            child.set_hexpand(True)
+            try:
+                if child.get_label():
+                    child.set_can_focus(False)
+                    child.connect("released", self.set_brush_mode, child.get_label())
+            except Exception as e:
+                ...
+
+    def set_brush_color(self, widget: any):
+        event_system.emit("set-brush-color", (widget.get_rgba(),))
+
+    def set_brush_size(self, widget: any):
+        event_system.emit("set-brush-size", (widget.get_value(),))
+
+    def set_brush_mode(self, widget: any, mode: str):
+        if mode in ["Save As"]: return
+
+        self.active_btn.set_active(False)
+        widget.set_active(True)
+        self.active_btn = widget
+
+        event_system.emit("set-brush-mode", (mode,))
+
+    def save_image(self, widget: any):
+        fpath = event_system.emit_and_await("save-as")
+        if not fpath: return
+        event_system.emit("save-image", (fpath,))
+

src/widgets/containers/container.py

@@ -0,0 +1,57 @@
+# Python imports
+
+# Lib imports
+import gi
+gi.require_version('Gtk', '3.0')
+
+from gi.repository import Gtk
+
+# Application imports
+from widgets.button_box import ButtonBox
+from widgets.draw_area import DrawArea
+
+
+class ScrollWindow(Gtk.ScrolledWindow):
+    def __init__(self):
+        super(ScrollWindow, self).__init__()
+ 
+        self._setup_styling()
+        self._setup_signals()
+        self._load_widgets()
+ 
+        self.show_all()
+
+
+    def _setup_styling(self):
+        self.set_hexpand(True)
+        self.set_vexpand(True)
+
+    def _setup_signals(self):
+        ...
+
+    def _load_widgets(self):
+        view_port = Gtk.Viewport()
+
+        view_port.add( DrawArea() )
+        self.add(view_port)
+
+class Container(Gtk.Box):
+    def __init__(self):
+        super(Container, self).__init__()
+ 
+        self._setup_styling()
+        self._setup_signals()
+        self._load_widgets()
+ 
+        self.show()
+
+
+    def _setup_styling(self):
+        self.set_orientation(Gtk.Orientation.VERTICAL)
+
+    def _setup_signals(self):
+        ...
+
+    def _load_widgets(self):
+        self.add( ButtonBox() )
+        self.add( ScrollWindow() )

src/widgets/controls/open_file_button.py

@@ -0,0 +1,78 @@
+# Python imports
+import os
+
+# Lib imports
+import gi
+gi.require_version('Gtk', '3.0')
+from gi.repository import Gtk
+from gi.repository import Gio
+
+# Application imports
+
+
+
+class OpenFileButton(Gtk.Button):
+    """docstring for OpenFileButton."""
+
+    def __init__(self):
+        super(OpenFileButton, self).__init__()
+
+        self._setup_styling()
+        self._setup_signals()
+        self._subscribe_to_events()
+        self._load_widgets()
+
+
+    def _setup_styling(self):
+        self.set_label("Open Image...")
+        self.set_image( Gtk.Image.new_from_icon_name("gtk-open", 4) )
+        self.set_always_show_image(True)
+        self.set_image_position(1) # Left - 0, Right = 1
+        self.set_hexpand(False)
+
+    def _setup_signals(self):
+        ...
+
+    def _subscribe_to_events(self):
+        event_system.subscribe("open-file", self._open_file)
+
+    def _load_widgets(self):
+        ...
+
+    def _open_file(self, widget = None, eve = None, gfile = None):
+        start_dir = None
+
+        if gfile and gfile.query_exists():
+            start_dir = gfile.get_parent()
+
+        chooser = Gtk.FileChooserDialog("Open Image...", None,
+                                        Gtk.FileChooserAction.OPEN,
+                                        (
+                                            Gtk.STOCK_CANCEL,
+                                            Gtk.ResponseType.CANCEL,
+                                            Gtk.STOCK_OPEN,
+                                            Gtk.ResponseType.OK
+                                        )
+        )
+
+        chooser.set_select_multiple(False)
+
+        try:
+            folder = widget.get_current_file().get_parent() if not start_dir else start_dir
+            chooser.set_current_folder( folder.get_path() )
+        except Exception as e:
+            ...
+
+        response = chooser.run()
+        if not response == Gtk.ResponseType.OK:
+            print("response")
+            chooser.destroy()
+            return _gfiles
+
+        filename = chooser.get_filename()
+        if not filename:
+            chooser.destroy()
+            return _gfile
+
+        chooser.destroy()
+        return filename

src/widgets/controls/save_as_button.py

@@ -0,0 +1,68 @@
+# Python imports
+import os
+
+# Lib imports
+import gi
+gi.require_version('Gtk', '3.0')
+from gi.repository import Gtk
+from gi.repository import Gio
+
+# Application imports
+
+
+
+class SaveAsButton(Gtk.Button):
+    def __init__(self):
+        super(SaveAsButton, self).__init__()
+
+        self._setup_styling()
+        self._setup_signals()
+        self._subscribe_to_events()
+        self._load_widgets()
+
+
+    def _setup_styling(self):
+        self.set_label("Save As")
+        self.set_image( Gtk.Image.new_from_icon_name("gtk-save-as", 4) )
+        self.set_always_show_image(True)
+        self.set_image_position(1) # Left - 0, Right = 1
+        self.set_hexpand(False)
+
+    def _setup_signals(self):
+        ...
+
+    def _subscribe_to_events(self):
+        event_system.subscribe("save-as", self._save_as)
+
+    def _load_widgets(self):
+        ...
+
+    def _save_as(self, widget = None, eve = None, gfile = None):
+        start_dir = None
+        _gfile    = None
+
+        chooser = Gtk.FileChooserDialog("Save File As...", None,
+                                        Gtk.FileChooserAction.SAVE,
+                                        (
+                                            Gtk.STOCK_CANCEL,
+                                            Gtk.ResponseType.CANCEL,
+                                            Gtk.STOCK_SAVE_AS,
+                                            Gtk.ResponseType.OK
+                                        )
+        )
+
+        response = chooser.run()
+        if not response == Gtk.ResponseType.OK:
+            chooser.destroy()
+            return _gfile
+
+        file = chooser.get_filename()
+        if not file:
+            chooser.destroy()
+            return _gfile
+
+        path = file if os.path.isabs(file) else os.path.abspath(file)
+
+        print(f"File To Save As:  {path}")
+        chooser.destroy()
+        return path

src/widgets/draw_area.py

@@ -0,0 +1,225 @@
+# Python imports
+from copy import copy, deepcopy
+
+# Lib imports
+import cairo
+import gi
+gi.require_version('Gtk', '3.0')
+
+from gi.repository import Gtk
+from gi.repository import Gdk
+
+# Application imports
+from libs.surface_manager import SurfaceManager
+from libs.event_collection import EventCollection
+
+from data.mouse_buttons import MouseButton
+
+from .surface import Surface
+
+from . import brushes
+
+
+class DrawArea(Gtk.DrawingArea):
+    def __init__(self):
+        super(DrawArea, self).__init__()
+
+        self.background_surface: Surface       = None
+        self.primary_surface: Surface          = None
+        self.intermediate_surface: Surface     = None
+        self.surface_manager: SurfaceManager   = SurfaceManager()
+        self.event_collection: EventCollection = EventCollection()
+
+        self.is_drawing: bool                  = False
+        self.brush_mode: str                   = "Line"
+        self.grid_brush: BrushBase             = getattr(brushes, "Grid")()
+        self.brush: BrushBase                  = getattr(brushes, self.brush_mode)()
+        self.brush_color                       = self.brush.color
+        self.brush_size                        = self.brush.size
+
+        self._setup_styling()
+        self._setup_signals()
+        self._subscribe_to_events()
+        self._load_widgets()
+
+        self._set_new_surface()
+ 
+
+    def _setup_styling(self):
+        margin_px = 24
+        self.set_margin_top(margin_px)
+        self.set_margin_left(margin_px)
+        self.set_margin_right(margin_px)
+        self.set_margin_end(margin_px)
+
+    def _setup_signals(self):
+        self.set_can_focus(True)
+        self.set_size_request(800, 600)
+
+        self.add_events(Gdk.EventMask.KEY_PRESS_MASK)
+        self.add_events(Gdk.EventMask.KEY_RELEASE_MASK)
+        self.add_events(Gdk.EventMask.BUTTON_PRESS_MASK)
+        self.add_events(Gdk.EventMask.BUTTON_RELEASE_MASK)
+        self.add_events(Gdk.EventMask.BUTTON1_MOTION_MASK)
+
+        self.connect("key-release-event", self._key_release_event)
+        self.connect("button-press-event", self._button_press_event)
+        self.connect("button-release-event", self._button_release_event)
+        self.connect("motion-notify-event", self._motion_notify_event)
+        self.connect("draw", self._draw)
+
+
+    def _subscribe_to_events(self):
+        event_system.subscribe("save-image", self._save_image)
+        event_system.subscribe("set-brush-color", self._set_brush_color)
+        event_system.subscribe("set-brush-size", self._set_brush_size)
+        event_system.subscribe("set-brush-mode", self._set_brush_mode)
+
+    def _load_widgets(self):
+        ...
+
+    def _set_new_surface(self):
+        size_w, \
+        size_h, \
+        image_surface = event_system.emit_and_await("get-image-size")
+
+        self.grid_brush.width     = size_w
+        self.grid_brush.height    = size_h
+        self.background_surface   = Surface(size_w, size_h)
+        self.primary_surface      = Surface(size_w, size_h)
+        self.intermediate_surface = Surface(size_w, size_h)
+
+        if image_surface:
+            self.primary_surface.create_new_area(image_surface)
+            self.primary_surface.set_image_data(image_surface.get_data())
+
+        self.event_collection.clear()
+        self.surface_manager.clear()
+
+        self.grid_brush.update(None)
+        self.set_size_request(size_w, size_h)
+        self.background_surface.update(self.grid_brush)
+        self.surface_manager.append( self.primary_surface )
+
+    def _save_image(self, fpath: str):
+        self.primary_surface.area.write_to_png(fpath)
+
+    def _do_save_image(self):
+        fpath = event_system.emit_and_await("save-as")
+        if not fpath: return
+        self._save_image(fpath)
+
+    def _set_brush_color(self, color: Gdk.RGBA):
+        self.brush       = getattr(brushes, self.brush_mode)()
+        self.brush_color = [color.red, color.green, color.blue, color.alpha]
+        self.brush.color = self.brush_color
+
+    def _set_brush_size(self, size: int):
+        self.brush_size  = size
+        self.brush       = getattr(brushes, self.brush_mode)()
+        self.brush.size  = self.brush_size
+
+    def _set_brush_mode(self, mode: str):
+        self.brush_mode  = mode
+        self.brush       = getattr(brushes, self.brush_mode)()
+        self.brush.color = self.brush_color
+        self.brush.size  = self.brush_size
+
+    def _button_press_event(self, widget, eve):
+        if not self.has_focus():
+            self.grab_focus()
+
+        if eve.type == Gdk.EventType.BUTTON_PRESS and eve.button == MouseButton.LEFT_BUTTON:
+            self.event_collection.clear()
+
+            self.is_drawing = True
+            self._set_brush_mode(self.brush_mode)
+            self.intermediate_surface.update(self.brush)
+            self.brush.update(eve)
+
+
+        if eve.type == Gdk.EventType.BUTTON_PRESS and eve.button == MouseButton.RIGHT_BUTTON:
+            ...
+
+    def _button_release_event(self, widget, eve):
+        if eve.type == Gdk.EventType.BUTTON_RELEASE and eve.button == MouseButton.LEFT_BUTTON:
+            self.is_drawing = False
+            self.intermediate_surface.history_manager.clear()
+
+            if not self.brush.is_valid: return
+    
+            self.primary_surface.update(self.brush)
+            self.queue_draw()
+
+        if eve.type == Gdk.EventType.BUTTON_RELEASE and eve.button == MouseButton.RIGHT_BUTTON:
+            ...
+
+    def _key_release_event(self, widget, eve):
+        keyname    = Gdk.keyval_name(eve.keyval)
+        modifiers  = Gdk.ModifierType(eve.get_state() & ~Gdk.ModifierType.LOCK_MASK)
+        is_control = True if modifiers & Gdk.ModifierType.CONTROL_MASK else False
+        is_shift   = True if modifiers & Gdk.ModifierType.SHIFT_MASK else False
+
+        if is_control:
+            if keyname == "z":
+                if len(self.primary_surface.history_manager) == 0: return
+                self.event_collection.append( self.primary_surface.history_manager.pop() )
+            elif keyname == "y":
+                if len(self.event_collection) == 0: return
+                self.primary_surface.history_manager.append( self.event_collection.pop() )
+            elif keyname == "n":
+                self._set_new_surface()
+            elif keyname == "s":
+                self._do_save_image()
+
+            self.queue_draw()
+
+
+    def _motion_notify_event(self, area, eve):
+        if not self.is_drawing: return
+        self.brush.update(eve)
+        self.queue_draw()
+
+    def _draw(self, area, brush: cairo.Context):
+        self._draw_background(area, brush)
+        self._draw_surfaces(area, brush)
+        self._draw_overlay(area, brush)
+
+        return False
+
+    def _draw_background(self, area, brush: cairo.Context):
+        # Note: While drawing, only overlay needs to re-calculate its stack.
+        # This can just copy what exists than re-calculating the surface.
+        if self.is_drawing:
+            brush.set_source_surface(self.background_surface.area, 0.0, 0.0)
+            brush.paint()
+            return
+
+        brush.set_source_surface(self.background_surface.area, 0.0, 0.0)
+        self.background_surface.draw()
+        brush.paint()
+
+    def _draw_surfaces(self, area, brush: cairo.Context):
+        # Note: While drawing, only overlay needs to re-calculate its stack.
+        # This can just copy what exists than re-calculating each surface.
+        if self.is_drawing:
+            for surface in self.surface_manager:
+                brush.set_source_surface(surface.area, 0.0, 0.0)
+                brush.paint()
+
+            return
+
+        for surface in self.surface_manager:
+            brush.set_source_surface(surface.area, 0.0, 0.0)
+            surface.draw()
+            brush.paint()
+
+    def _draw_overlay(self, area, brush: cairo.Context):
+        # Note: When NOT drawing, no overlay data should exist nor be processed...
+        if not self.is_drawing:
+            self.intermediate_surface.clear_surface()
+            return
+
+        brush.set_source_surface(self.intermediate_surface.area, 0.0, 0.0)
+        self.intermediate_surface.draw()
+        brush.paint()

src/widgets/image_type_dialog.py

@@ -0,0 +1,135 @@
+# Python imports
+import ctypes
+
+# Lib imports
+import cairo
+import gi
+
+gi.require_version('Gtk', '3.0')
+
+from gi.repository import GObject
+from gi.repository import Gtk
+from gi.repository import GdkPixbuf
+
+# Application imports
+from .controls.open_file_button import OpenFileButton
+from data.cbindings import pixbuf2cairo
+
+
+class ImageTypeDialog(Gtk.Dialog):
+    def __init__(self):
+        super(ImageTypeDialog, self).__init__()
+
+        self.img_path = None
+
+        self._setup_styling()
+        self._setup_signals()
+        self._subscribe_to_events()
+        self._load_widgets()
+
+
+    def _setup_styling(self):
+        self.set_size_request(420, 320)
+
+
+    def _setup_signals(self):
+        ...
+
+    def _subscribe_to_events(self):
+        event_system.subscribe("get-image-size", self._get_image_size)
+
+    def _load_widgets(self):
+        vbox            = self.get_content_area()
+        hbox1           = Gtk.Box()
+        hbox2           = Gtk.Box()
+        head_lbl        = Gtk.Label("Image Size")
+        size_w_lbl      = Gtk.Label("Width:")
+        size_h_lbl      = Gtk.Label("Height:")
+        open_file_btn   = OpenFileButton()
+
+        self.size_w_btn = Gtk.SpinButton()
+        self.size_h_btn = Gtk.SpinButton()
+
+        self.size_w_btn.set_numeric(True)
+        self.size_w_btn.set_digits(0)
+        self.size_w_btn.set_snap_to_ticks(True)
+        self.size_w_btn.set_increments(1.0, 100.0)
+        self.size_w_btn.set_range(32.0, 10000.0)
+        self.size_w_btn.set_value(800.0)
+
+        self.size_h_btn.set_numeric(True)
+        self.size_h_btn.set_digits(0)
+        self.size_h_btn.set_snap_to_ticks(True)
+        self.size_h_btn.set_increments(1.0, 100.0)
+        self.size_h_btn.set_range(32.0, 10000.0)
+        self.size_h_btn.set_value(600.0)
+
+        hbox1.set_margin_top(24)
+        head_lbl.set_hexpand(True)
+        size_w_lbl.set_hexpand(True)
+        size_h_lbl.set_hexpand(True)
+        open_file_btn.set_hexpand(True)
+        open_file_btn.set_margin_top(24)
+        open_file_btn.set_margin_bottom(24)
+        open_file_btn.set_margin_left(24)
+        open_file_btn.set_margin_right(24)
+        self.size_w_btn.set_margin_right(24)
+        self.size_h_btn.set_margin_right(24)
+        self.size_w_btn.set_hexpand(True)
+        self.size_h_btn.set_hexpand(True)
+
+        open_file_btn.connect("button-release-event", self._open_files)
+
+        vbox.add(head_lbl)
+        hbox1.add(size_w_lbl)
+        hbox1.add(self.size_w_btn)
+        hbox2.add(size_h_lbl)
+        hbox2.add(self.size_h_btn)
+        vbox.add(hbox1)
+        vbox.add(hbox2)
+        vbox.add(open_file_btn)
+
+        self.add_button("Continue", Gtk.ResponseType.OK)
+
+        vbox.show_all()
+
+    def _get_image_size(self):
+        self.img_path = None
+
+        response = self.run()
+        if response == -4 or response == Gtk.ResponseType.OK:
+            self.hide()
+
+        surface       = None
+        width, height = self.size_w_btn.get_value_as_int(), self.size_h_btn.get_value_as_int()
+        if self.img_path:
+            pixbuf  = Gtk.Image.new_from_file(self.img_path).get_pixbuf()
+            width   = pixbuf.get_width()
+            height  = pixbuf.get_height()
+            surface = self._pixels_to_cairo_surface(pixbuf, width, height)
+
+        return width, height, surface
+
+    def _open_files(self, widget, eve):
+        self.img_path = event_system.emit_and_await("open-file")
+
+
+    def _pixels_to_cairo_surface(
+        self,
+        pixbuf: GdkPixbuf.Pixbuf,
+        width: int,
+        height: int
+    ) -> cairo.ImageSurface:
+        pixbuf_ptr   = int(hash(pixbuf))  # WARNING: not stable across runs
+        cairo_data   = pixbuf2cairo.pixbuf_to_cairo_data(pixbuf_ptr)
+        cairo_stride = width * 4
+
+        return cairo.ImageSurface.create_for_data(
+            bytearray(cairo_data),
+            cairo.FORMAT_ARGB32,
+            width,
+            height,
+            cairo_stride
+        )
+
+        return surface

src/widgets/surface.py

@@ -0,0 +1,53 @@
+# Python imports
+
+# Lib imports
+import cairo
+
+
+# Application imports
+from libs.history_manager import HistoryManager
+
+from data.event import Event
+
+
+class Surface:
+    def __init__(self, w = 1, h = 1):
+        super(Surface, self).__init__()
+
+        self.image_data = None
+
+        self.history_manager: HistoryManager = HistoryManager()
+        self.create_new_area(None, w, h)
+
+
+    # Note:  https://martimm.github.io/gnome-gtk3/content-docs/tutorial/Cairo/drawing-model.html
+    def create_new_area(self, surface: cairo.ImageSurface = None, w: int = None, h: int = None):
+        if surface:
+            self.area  = surface
+            self.brush = cairo.Context(surface)
+            return
+
+        self.area: cairo.ImageSurface = cairo.ImageSurface(cairo.FORMAT_ARGB32, w, h)
+        self.brush: cairo.Context     = cairo.Context(self.area)
+
+    def set_image_data(self, data: any):
+        self.image_data = bytearray(data)
+
+    def update(self, event: Event):
+        self.history_manager.append(event)
+
+    def draw(self):
+        if not self.image_data:
+            self.clear_surface()
+        elif self.image_data:
+            dest_data = self.area.get_data()
+            dest_data[:len(self.image_data)] = self.image_data[:]
+
+        for event in self.history_manager:
+            if not event.is_valid: continue
+            event.process(self.brush)
+
+    def clear_surface(self):
+        self.brush.set_operator(cairo.OPERATOR_CLEAR)
+        self.brush.paint()
+        self.brush.set_operator(cairo.OPERATOR_OVER)

src/window.py

@@ -0,0 +1,59 @@
+# Python imports
+import signal
+
+# Lib imports
+import gi
+gi.require_version('Gtk', '3.0')
+
+from gi.repository import Gtk
+from gi.repository import GLib
+
+# Application imports
+from widgets.containers.container import Container
+from widgets.image_type_dialog import ImageTypeDialog
+
+
+class Window(Gtk.ApplicationWindow):
+    def __init__(self):
+        super(Window, self).__init__()
+
+        self._setup_styling()
+        self._setup_signals()
+        self._load_widgets()
+
+        self.show()
+
+
+    def _setup_styling(self):
+        _min_width  = 720
+        _min_height = 480
+        _width      = 1200
+        _height     = 800
+
+        self.set_title(f"{APP_NAME}")
+        self.set_gravity(5)  # 5 = CENTER
+        self.set_position(1) # 1 = CENTER, 4 = CENTER_ALWAYS
+        self.set_size_request(_min_width, _min_height)
+        self.set_default_size(_width, _height)
+
+        # self.set_interactive_debugging(True)
+
+    def _setup_signals(self):
+        self.connect("delete-event", self.stop)
+        GLib.unix_signal_add(GLib.PRIORITY_DEFAULT, signal.SIGINT, self.stop)
+
+    def _load_widgets(self):
+        image_type_dialog = ImageTypeDialog()
+
+        image_type_dialog.set_attached_to(self)
+
+        self.add( Container() )
+
+    def start(self):
+        Gtk.main()
+
+    def stop(self, widget = None, eve = None):
+        size = self.get_size()
+        pos  = self.get_position()
+
+        Gtk.main_quit()