gizeh 0.1.07

Surfaces

A Surface is a rectangle of fixed dimensions (in pixels), on which you will draw elements, and that you can save or export as an image:

import gizeh

# initialize surface
surface = gizeh.Surface(width=320, height=260) # in pixels

# Now make a shape and draw it on the surface
circle = gizeh.circle(r=30, xy= [40,40], fill=(1,1,1))
circle.draw(surface)

# Now export the surface
surface.get_npimage() # returns a (width x height x 3) numpy array
surface.write_to_png("circle.png") # doesn't require scipy, but image is flipped

Elements

Basic elements are circles, rectangles, lines, texts, etc., that you can draw on a surface using my_element.draw(surface). You can specify the properties and coordinates of these elements at creation time:

• xy : coordinates of the center of the object. (0,0), which is the defaut, corresponds to the bottom left corner of the final picture.

• angle : angle (in radians) of the rotation of the element around its center xy.

• fill : what will fill the element (default is no fill). Can be a color (R,G,B), a color gradient, an image, etc. See section below.

• stroke : What will fill the element’s contour. Same rules as for fill.

• stroke_width : the width (in pixels) of the element’s contour. Default is 0 (no stroke).

Examples of elements:

Pi = 3.14
circ = gizeh.circle(r=30, xy=(50,50), fill=(1,1,1))
rect = gizeh.rectangle(lx=60.3, ly=45, xy=(60,70), fill=(0,1,0), angle=Pi/8)
sqr = gizeh.square(l=20, stroke=(1,1,1), stroke_width= 1.5)
arc = gizeh.arc(r=20, a1=Pi/4, a2=3*Pi/4, fill=(1,1,1))
text = gizeh.text("Hello world", fontfamily="Impact",  fontsize=40,
                  fill=(1,1,1), xy=(100,100), angle=Pi/12)
polygon = gizeh.polygon(r=40, n=5, angle=np.pi/4, xy=[40,50], fill=(1,0,1))
line = gizeh.polyline(points=[(0,0), (20,30), (40,40), (0,10)], stroke_width=3,
                     stroke=(1,0,0), fill=(0,1,0))

Transformations

Any element can be tranformed (translated, rotated or scaled). All transformations are outplace: they do not modify the original element, they create a modified version of it.

Examples:

square_1 = gizeh.square(l=20, xy = [30,35], fill=(1,0,0))
square_2 = square_1.rotate(Pi/8) # rotation around [0,0] by default
square_3 = square_2.rotate(Pi/4, center=[10,15]) # rotation around a center
square_4 = square_1.scale(2) # two times bigger
square_5 = square1.scale(sx=2, sy=3) # width times 2, height times 3
square_6 = square_1.scale(2, center=[30,30]) # zoom: scales around a center
square_7 = square_1.translate(xy=[5,15]) # translation

Groups

A Group is a collection of elements which will be transformed and drawn together. The elements can be a basic element (square, circle…) or even groups.

Examples:

square = gizeh.square(l=20, fill=(1,0,0), xy=(40,40))
circle = gizeh.circle(r=20, fill=(1,2,0), xy=(50,30))
group_1 = gizeh.Group([square, circle])
group_2 = group.translate(xy=[30,30]).rotate(Pi/4)
group_3 = gizeh.Group([circle, group_1])

surface = gizeh.Surface(width=300,height=200)
group.draw(surface)
group_1.draw(surface)
group_2.draw(surface)
group_3.draw(surface)
surface.write_to_png("my_masterwork.png")

That’s all folks !

That’s about all there is to know. To go further, see the examples in the examples folder or (wishful thinking) on the Web.