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Diffstat (limited to '')
-rwxr-xr-x | share/extensions/color_custom.py | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/share/extensions/color_custom.py b/share/extensions/color_custom.py new file mode 100755 index 0000000..87dd5bd --- /dev/null +++ b/share/extensions/color_custom.py @@ -0,0 +1,74 @@ +#!/usr/bin/env python +"""Custom color function per channel of selected objects""" + +import ast +import operator as op +import inkex + +OPS = { + ast.Add: op.add, + ast.Sub: op.sub, + ast.Mult: op.mul, + ast.Div: op.truediv, + ast.Pow: op.pow, + ast.BitXor: op.xor, + ast.USub: op.neg, +} + + +def eval_expr(expr, namespace): + """ + >>> eval_expr('2^6') + 4 + >>> eval_expr('2**6') + 64 + >>> eval_expr('1 + 2*3**(4^5) / (6 + -7)') + -5.0 + """ + return _eval(ast.parse(expr, mode="eval").body, namespace) + + +def _eval(node, namespace): + if isinstance(node, ast.Num): # <number> + return node.n + if isinstance(node, ast.Name): # <variable> (must be in namespace) + return namespace[node.id] + if isinstance(node, ast.BinOp): # <left> <operator> <right> + return OPS[type(node.op)]( + _eval(node.left, namespace), _eval(node.right, namespace) + ) + if isinstance(node, ast.UnaryOp): # <operator> <operand> e.g., -1 + return OPS[type(node.op)](_eval(node.operand, namespace)) + raise TypeError(node) + + +class Custom(inkex.ColorExtension): + """Custom colour functions per channel""" + + def add_arguments(self, pars): + pars.add_argument("--tab") + pars.add_argument("-r", "--r", default="r", help="red channel function") + pars.add_argument("-g", "--g", default="g", help="green channel function") + pars.add_argument("-b", "--b", default="b", help="blue channel function") + pars.add_argument( + "-s", "--scale", type=float, default=1.0, help="The input (r,g,b) range" + ) + + def modify_color(self, name, color): + opt = self.options + factor = 255.0 / opt.scale + # add stuff to be accessible from within the custom color function here. + namespace = { + "r": float(color.red) / factor, + "g": float(color.green) / factor, + "b": float(color.blue) / factor, + } + + color.red = int(eval_expr(opt.r.strip(), namespace) * factor) + color.green = int(eval_expr(opt.g.strip(), namespace) * factor) + color.blue = int(eval_expr(opt.b.strip(), namespace) * factor) + return color + + +if __name__ == "__main__": + Custom().run() |