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fgdata/Nasal/canvas/api/transform.nas
2020-04-30 08:59:25 +01:00

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#-------------------------------------------------------------------------------
# Transform
#-------------------------------------------------------------------------------
# A transformation matrix which is used to transform an #Element on the canvas.
# The dimensions of the matrix are 3x3 where the last row is always 0 0 1:
#
# a c e
# b d f
# 0 0 1
#
# See http://www.w3.org/TR/SVG/coords.html#TransformMatrixDefined for details.
#
var Transform = {
new: func(node, vals = nil) {
var m = {
parents: [Transform],
_node: node,
a: node.getNode("m[0]", 1),
b: node.getNode("m[1]", 1),
c: node.getNode("m[2]", 1),
d: node.getNode("m[3]", 1),
e: node.getNode("m[4]", 1), #tx
f: node.getNode("m[5]", 1), #ty
};
var use_vals = typeof(vals) == "vector" and size(vals) == 6;
# initialize to identity matrix
m.a.setDoubleValue(use_vals ? vals[0] : 1);
m.b.setDoubleValue(use_vals ? vals[1] : 0);
m.c.setDoubleValue(use_vals ? vals[2] : 0);
m.d.setDoubleValue(use_vals ? vals[3] : 1);
m.e.setDoubleValue(use_vals ? vals[4] : 0);
m.f.setDoubleValue(use_vals ? vals[5] : 0);
return m;
},
setTranslation: func() {
var trans = _arg2valarray(arg);
me.e.setDoubleValue(trans[0]);
me.f.setDoubleValue(trans[1]);
return me;
},
# Set rotation (Optionally around a specified point instead of (0,0))
#
# setRotation(rot)
# setRotation(rot, cx, cy)
#
# @note If using with rotation center different to (0,0) do not use
# #setTranslation as it would interfere with the rotation.
setRotation: func(angle) {
var center = _arg2valarray(arg);
var s = math.sin(angle);
var c = math.cos(angle);
me.a.setDoubleValue(c); me.c.setDoubleValue(-s);
me.b.setDoubleValue(s); me.d.setDoubleValue(c);
if (size(center) == 2) {
me.e.setDoubleValue((-center[0] * c) + (center[1] * s) + center[0]);
me.f.setDoubleValue((-center[0] * s) - (center[1] * c) + center[1]);
}
return me;
},
# Set scale (either as parameters or array)
#
# If only one parameter is given its value is used for both x and y
# setScale(x, y)
# setScale([x, y])
setScale: func {
var scale = _arg2valarray(arg);
me.a.setDoubleValue(scale[0]);
me.d.setDoubleValue(size(scale) >= 2 ? scale[1] : scale[0]);
return me;
},
getScale: func() {
# TODO handle rotation
return [me.a.getValue(), me.d.getValue()];
}
};