Hello,
I am using clutter-cairo 0.82 and clutter 0.8.8 (pyclutter, actually,
and pycairo) to create a custom GradientRectangle object to draw a basic
rectangular gradient.
The class extends CloneTexture and passes a CairoTexture object to the
superclass constructor after drawing the requested gradient.
I've been encountering two issues and am having trouble finding examples
or documentation related to them.
One, i'm not sure how to repaint the CairoTexture object on each redraw
with do_paint(), so any overlapping windows erase those parts of the
gradient. Two, when i specify a 1024x1024 texture object and a 1024x768
rectangle in cairo, the gradient is only drawn over about the top 2/3rds
of the window. The size of the window itself is 1024x768.
I've pasted the __init__ function below. Sorry for the long email, I'm
fairly new to Clutter and am probably missing something obvious. Any
ideas or comments would help!
Thanks!
Christine
def __init__(self, width, height, colors = None, alphas = None, x =
0, y = 0, visible = True, depth = 0, rotation = 0.0,
scale_x = 1.0, scale_y = 1.0, name = None):
# Find the nearest power of 2 texture size which will fit this
gradient
import math
widthlog2, heightlog2 = math.log(width, 2), math.log(height, 2)
tex_size_width, tex_size_height = math.pow(2,
int(math.ceil(widthlog2))), math.pow(2, int(math.ceil(heightlog2)))
#Create texture and pass to CloneTexture superclass constructor
self.cr_tex = CairoTexture(tex_size_width, tex_size_height)
cr = self.cr_tex.cairo_create() # Returns the
cluttercairo.CairoContext object to draw with
# Clears the background to white
cr.set_operator(cairo.OPERATOR_CLEAR)
# Begins painting on the canvas
cr.paint()
# Default operator
cr.set_operator(cairo.OPERATOR_OVER)
# Draw the proper sized rectangle to apply the gradient to
cr.rectangle(0.0, 0.0, width, height)
# Creates a linear gradient along the line defined by x0, y0 and
x1, y1 (the respective parameters of the constructor)
# In this case to create a straight up and down gradient we
define the center y point and the beginning and ending xs.
linear = cairo.LinearGradient(width/2, 0, width/2, height)
# Hardcoded gradient test values
linear.add_color_stop_rgba(0, 0, 0.3, 0.8, 0.8)
linear.add_color_stop_rgba(1, 0, 0.8, 0.3, 0.6)
cr.set_source(linear)
cr.fill()
clutter.CloneTexture.__init__(self, self.cr_tex)
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