## demonstrate rotation and alpha blending
import PyArt

c = PyArt.Canvas(356, 256, bg=0x7f7f7f)
c.gstate.fill = 0xFFFFFF
c.gstate.font_size = 48

def rotate_alpha_blend_text(can,off_x, text, dw, n, end_alpha):
    "decrease alpha linearly over the range of n points"
    dalpha = end_alpha/n
    for ii in range(n):
        can.gsave()
        can.rotate(dw*ii)
        # print dw*ii
        can.gstate.fill_opacity = end_alpha-ii*dalpha
        # print "alpha = ", can.gstate.fill_opacity
        can.drawString(off_x,0, text)
        can.grestore()

c.translate(85,220) # controls centering of the figure

n = 8.0
dw = 90.0/n
off_x = 5
text = "Pingo Art"
c.gsave()
c.rotate(-dw*n)
c.gstate.fill = 0xFFFFFF
rotate_alpha_blend_text(c, off_x, text, dw, n, end_alpha=.9)
c.grestore()
c.gstate.fill = 0x000000
c.drawString(off_x,0, text)
c.save("demo_rotate_alpha_text.png")


# here's a rotation example without alpha blending

c = PyArt.Canvas(256, 256, bg=0x7f7f7f)
c.gstate.fill = 0xFFFFFF
c.gstate.font_size = 18
c.translate(128,128)

def rotate_text(can,off_x, text, dw, n):
    for ii in range(n):
        can.gsave()
        can.rotate(dw*ii)
        can.drawString(off_x,0, text)
        can.grestore()

rotate_text(c, 15, "rotated text", 30, 12)
c.save("demo_rotate_text.png")