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#!/usr/bin/env python
import sys
import traceback
from math import pi
import pygtk
pygtk.require ("2.0")
import gobject
gobject.threads_init()
import pygst
pygst.require('0.10')
import gst
import cairo
WIDTH, HEIGHT = 640, 480
FRAMES = 300
FRAMERATE = 15
class PyGstBufferDraw(gst.Element):
_sinkpadtemplate = gst.PadTemplate ("sink",
gst.PAD_SINK,
gst.PAD_ALWAYS,
gst.caps_from_string ("video/x-raw-rgb,bpp=32,depth=32,blue_mask=-16777216,green_mask=16711680, red_mask=65280, alpha_mask=255,width=[ 1, 2147483647 ],height=[ 1, 2147483647 ],framerate=[ 0/1, 2147483647/1 ]"))
_srcpadtemplate = gst.PadTemplate ("src",
gst.PAD_SRC,
gst.PAD_ALWAYS,
gst.caps_from_string ("video/x-raw-rgb,bpp=32,depth=32,blue_mask=-16777216,green_mask=16711680, red_mask=65280, alpha_mask=255,width=[ 1, 2147483647 ],height=[ 1, 2147483647 ],framerate=[ 0/1, 2147483647/1 ]"))
def __init__(self):
gst.Element.__init__(self)
self.sinkpad = gst.Pad(self._sinkpadtemplate, "sink")
self.sinkpad.set_chain_function(self.chainfunc)
self.sinkpad.set_event_function(self.eventfunc)
self.sinkpad.set_getcaps_function(gst.Pad.proxy_getcaps)
self.sinkpad.set_setcaps_function(gst.Pad.proxy_setcaps)
self.add_pad (self.sinkpad)
self.srcpad = gst.Pad(self._srcpadtemplate, "src")
self.srcpad.set_event_function(self.srceventfunc)
self.srcpad.set_query_function(self.srcqueryfunc)
self.srcpad.set_getcaps_function(gst.Pad.proxy_getcaps)
self.srcpad.set_setcaps_function(gst.Pad.proxy_setcaps)
self.add_pad (self.srcpad)
def chainfunc(self, pad, buffer):
try:
outbuf = buffer.copy_on_write ()
self.draw_on (outbuf)
return self.srcpad.push (outbuf)
except:
return GST_FLOW_ERROR
def eventfunc(self, pad, event):
return self.srcpad.push_event (event)
def srcqueryfunc (self, pad, query):
return self.sinkpad.query (query)
def srceventfunc (self, pad, event):
return self.sinkpad.push_event (event)
def draw_on (self, buf):
try:
caps = buf.get_caps()
width = caps[0]['width']
height = caps[0]['height']
framerate = caps[0]['framerate']
surface = cairo.ImageSurface.create_for_data (buf, cairo.FORMAT_ARGB32, width, height, 4 * width)
ctx = cairo.Context(surface)
except:
print "Failed to create cairo surface for buffer"
traceback.print_exc()
return
try:
center_x = width/4
center_y = 3*height/4
# draw a circle
radius = float (min (width, height)) * 0.25
ctx.set_source_rgba (0.0, 0.0, 0.0, 0.9)
ctx.move_to (center_x, center_y)
ctx.arc (center_x, center_y, radius, 0, 2.0*pi)
ctx.close_path()
ctx.fill()
ctx.set_source_rgba (1.0, 1.0, 1.0, 1.0)
ctx.set_font_size(0.3 * radius)
txt = "Hello World"
extents = ctx.text_extents (txt)
ctx.move_to(center_x - extents[2]/2, center_y + extents[3]/2)
ctx.text_path(txt)
ctx.fill()
except:
print "Failed cairo render"
traceback.print_exc()
gobject.type_register(PyGstBufferDraw)
pipe = gst.Pipeline()
vt = gst.element_factory_make ("videotestsrc")
cf = gst.element_factory_make ("capsfilter")
c1 = PyGstBufferDraw()
color = gst.element_factory_make ("ffmpegcolorspace")
scale = gst.element_factory_make ("videoscale")
q1 = gst.element_factory_make ("queue")
sink = gst.element_factory_make ("autovideosink")
caps = gst.caps_from_string ("video/x-raw-rgb,width=%d,height=%d,framerate=%d/1" % (WIDTH, HEIGHT, FRAMERATE))
cf.set_property ("caps", caps)
vt.set_property ("num-buffers", FRAMES)
pipe.add (vt, cf, c1, q1, color, scale, sink)
gst.element_link_many (vt, cf, c1, q1, color, scale, sink)
def on_eos (bus, msg):
mainloop.quit()
bus = pipe.get_bus()
bus.add_signal_watch()
bus.connect('message::eos', on_eos)
pipe.set_state (gst.STATE_PLAYING)
mainloop = gobject.MainLoop()
try:
mainloop.run()
except:
pass
pipe.set_state (gst.STATE_NULL)
pipe.get_state (gst.CLOCK_TIME_NONE)
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