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# Live video input from display class.
import gl
import GL
# The live video input class.
# Only instantiate this if have_video is true!
class DisplayVideoIn:
# Initialize an instance. Arguments:
# vw, vh: size of the video window data to be captured.
# position defaults to 0, 0 but can be set later
def __init__(self, pktmax, vw, vh, type):
self.pktmax = pktmax
self.realwidth, self.realheight = vw, vh
if type <> 'rgb':
raise 'Incorrent video data type', type
self.type = type
self.width = vw
self.height = vh
#
# Open dummy window
#
gl.foreground()
gl.noport()
self.wid = gl.winopen('DisplayVideoIn')
self.x0 = 0
self.x1 = self.x0 + self.width - 1
self.y0 = 0
self.y1 = self.y0 + self.height - 1
# Compute # full lines per packet
self.lpp = pktmax / self.linewidth()
if self.lpp <= 0:
raise 'No lines in packet', self.linewidth()
self.pktsize = self.lpp*self.linewidth()
self.data = None
self.old_data = None
self.dataoffset = 0
self.lpos = 0
self.hints = 0
# Change the size of the video being displayed.
def resizevideo(self, vw, vh):
self.width = vw
self.height = vh
self.x1 = self.x0 + self.width - 1
self.y1 = self.y0 + self.height - 1
def positionvideo(self, x, y):
self.x0 = x
self.y0 = y
self.x1 = self.x0 + self.width - 1
self.y1 = self.y0 + self.height - 1
# Remove an instance.
# This turns off continuous capture.
def close(self):
gl.winclose(self.wid)
# Get the length in bytes of a video line
def linewidth(self):
return self.width*4
# Get the next video packet.
# This returns (lpos, data) where:
# - lpos is the line position
# - data is a piece of data
# The dimensions of data are:
# - pixel depth = 1 byte
# - scan line width = self.width (the vw argument to __init__())
# - number of scan lines = self.lpp (PKTMAX / vw)
def getnextpacket(self):
if not self.data or self.dataoffset >= len(self.data):
self.old_data = self.data
self.data = gl.readdisplay(self.x0, self.y0, \
self.x1, self.y1, self.hints)
self.dataoffset = 0
self.lpos = 0
data = self.data[self.dataoffset:self.dataoffset+self.pktsize]
while self.old_data and \
self.dataoffset+self.pktsize < len(self.data):
odata = self.old_data[self.dataoffset: \
self.dataoffset+self.pktsize]
if odata <> data:
break
print 'skip', self.lpos
self.lpos = self.lpos + self.lpp
self.dataoffset = self.dataoffset + self.pktsize
data = self.data[self.dataoffset:\
self.dataoffset+self.pktsize]
lpos = self.lpos
self.dataoffset = self.dataoffset + self.pktsize
self.lpos = self.lpos + self.lpp
return lpos, data
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