def blend_xy_sep_transform(trans1, trans2):
"""
If trans1 and trans2 are SeparableTransformation instances, you can
build a new SeparableTransformation from them by extracting the x and y
bounding points and functions and recomposing a new SeparableTransformation
This function extracts all the relevant bits from trans1 and
trans2 and returns the new Transformation instance. This is
useful, for example, if you want to specify x in data coordinates
and y in axes coordinates.
"""
inboxx = trans1.get_bbox1()
inboxy = trans2.get_bbox1()
outboxx = trans1.get_bbox2()
outboxy = trans2.get_bbox2()
xminIn = inboxx.ll().x()
xmaxIn = inboxx.ur().x()
xminOut = outboxx.ll().x()
xmaxOut = outboxx.ur().x()
yminIn = inboxy.ll().y()
ymaxIn = inboxy.ur().y()
yminOut = outboxy.ll().y()
ymaxOut = outboxy.ur().y()
funcx = trans1.get_funcx()
funcy = trans2.get_funcy()
boxin = Bbox(Point(xminIn, yminIn), Point(xmaxIn, ymaxIn))
boxout = Bbox(Point(xminOut, yminOut), Point(xmaxOut, ymaxOut))
return SeparableTransformation(boxin, boxout, funcx, funcy)
def bbox_all(bboxes):
"""
Return the Bbox that bounds all bboxes
"""
# this is a good candidate to move to _transforms
assert (len(bboxes))
if len(bboxes) == 1: return bboxes[0]
bbox = bboxes[0]
minx = bbox.xmin()
miny = bbox.ymin()
maxx = bbox.xmax()
maxy = bbox.ymax()
for bbox in bboxes[1:]:
thisminx = bbox.xmin()
thisminy = bbox.ymin()
thismaxx = bbox.xmax()
thismaxy = bbox.ymax()
if thisminx < minx: minx = thisminx
if thismaxx > maxx: maxx = thismaxx
if thisminy < miny: miny = thisminy
if thismaxy > maxy: maxy = thismaxy
return Bbox(Point(Value(minx), Value(miny)), Point(Value(maxx),
Value(maxy)))
def inverse_transform_bbox(trans, bbox):
'inverse transform the bbox'
xmin, xmax = bbox.intervalx().get_bounds()
ymin, ymax = bbox.intervaly().get_bounds()
xmin, ymin = trans.inverse_xy_tup((xmin, ymin))
xmax, ymax = trans.inverse_xy_tup((xmax, ymax))
return Bbox(Point(Value(xmin), Value(ymin)), Point(Value(xmax),
Value(ymax)))
def scale_sep_transform(sx, sy):
"""
Return a pure scale transformation as a SeparableTransformation;
sx and sy are LazyValue instances (Values or binary opertations on
values)
"""
bboxin = unit_bbox()
bboxout = Bbox(Point(zero(), zero()), Point(sx, sy))
return SeparableTransformation(bboxin, bboxout, Func(IDENTITY),
Func(IDENTITY))
def lbwh_to_bbox(l, b, w, h):
return Bbox(Point(Value(l), Value(b)), Point(Value(l + w), Value(b + h)))
def unit_bbox():
"""
Get a 0,0 -> 1,1 Bbox instance
"""
return Bbox(origin(), Point(one(), one()))