def _render_prepare(self, cr):
"""Prepares a blank pixbuf & other details for later rendering.
Called when handling "draw" events. The size and shape of the
returned pixbuf (wrapped in a tile-accessible and read/write
lib.pixbufsurface.Surface) is determined by the Cairo clipping
region that expresses what we've been asked to redraw, and by
the TDW's own view transformation of the document.
"""
# Determine what to draw, and the nature of the reveal.
allocation = self.get_allocation()
w, h = allocation.width, allocation.height
device_bbox = (0, 0, w, h)
clip_rect, sparse = self._render_get_clip_region(cr, device_bbox)
x, y, w, h = device_bbox
# Use a copy of the cached translation matrix for this
# rendering. It'll need scaling if using a mipmap level
# greater than zero.
transformation = cairo.Matrix(*self._get_model_view_transformation())
# HQ rendering causes a very clear slowdown on some hardware.
# Probably could avoid this entirely by rendering differently,
# but for now, if the canvas is being panned around,
# just render more simply.
if self._hq_rendering:
mipmap_level = max(0, int(floor(log(1.0/self.scale, 2))))
else:
mipmap_level = max(0, int(ceil(log(1/self.scale, 2))))
# OPTIMIZE: If we would render tile scanlines,
# OPTIMIZE: we could probably use the better one above...
mipmap_level = min(mipmap_level, tiledsurface.MAX_MIPMAP_LEVEL)
transformation.scale(2**mipmap_level, 2**mipmap_level)
# bye bye device coordinates
cr.save() # >>>CONTEXT1
cr.transform(transformation)
cr.save() # >>>CONTEXT2
# calculate the final model bbox with all the clipping above
x1, y1, x2, y2 = cr.clip_extents()
if not self.is_translation_only():
# Looks like cairo needs one extra pixel rendered for interpolation at the border.
# If we don't do this, we get dark stripe artefacts when panning while zoomed.
x1 -= 1
y1 -= 1
x2 += 1
y2 += 1
x1, y1 = int(floor(x1)), int(floor(y1))
x2, y2 = int(ceil(x2)), int(ceil(y2))
# We always render with alpha to get hardware acceleration,
# even when we could avoid using the alpha channel. Speedup
# factor 3 for ATI/Radeon Xorg driver (and hopefully others).
# https://bugs.freedesktop.org/show_bug.cgi?id=28670
surface = pixbufsurface.Surface(x1, y1, x2-x1+1, y2-y1+1)
return transformation, surface, sparse, mipmap_level, clip_rect
def render_prepare(self, cr, device_bbox):
if device_bbox is None:
allocation = self.get_allocation()
w, h = allocation.width, allocation.height
device_bbox = (0, 0, w, h)
# logger.debug('device bbox: %r', tuple(device_bbox))
clip_region, sparse = self.render_get_clip_region(cr, device_bbox)
x, y, w, h = device_bbox
# fill it all white, though not required in the most common case
if self.visualize_rendering:
# grey
tmp = random.random()
cr.set_source_rgb(tmp, tmp, tmp)
cr.paint()
transformation = cairo.Matrix(*self._get_model_view_transformation())
# choose best mipmap
hq_zoom = False
if self.app and self.app.preferences['view.high_quality_zoom']:
hq_zoom = True
if hq_zoom:
# can cause a very clear slowdown on some hardware
# (we probably could avoid this by doing rendering differently)
mipmap_level = max(0, int(floor(log(1.0/self.scale, 2))))
else:
mipmap_level = max(0, int(ceil(log(1/self.scale, 2))))
# OPTIMIZE: if we would render tile scanlines, we could probably use the better one above...
mipmap_level = min(mipmap_level, tiledsurface.MAX_MIPMAP_LEVEL)
transformation.scale(2**mipmap_level, 2**mipmap_level)
# bye bye device coordinates
cr.save() # >>>CONTEXT1
cr.transform(transformation)
cr.save() # >>>CONTEXT2
# calculate the final model bbox with all the clipping above
x1, y1, x2, y2 = cr.clip_extents()
if not self.is_translation_only():
# Looks like cairo needs one extra pixel rendered for interpolation at the border.
# If we don't do this, we get dark stripe artefacts when panning while zoomed.
x1 -= 1
y1 -= 1
x2 += 1
y2 += 1
x1, y1 = int(floor(x1)), int(floor(y1))
x2, y2 = int(ceil(x2)), int(ceil(y2))
# We render with alpha just to get hardware acceleration, we
# don't actually use the alpha channel. Speedup factor 3 for
# ATI/Radeon Xorg driver (and hopefully others).
# https://bugs.freedesktop.org/show_bug.cgi?id=28670
surface = pixbufsurface.Surface(x1, y1, x2-x1+1, y2-y1+1)
return transformation, surface, sparse, mipmap_level, clip_region
def render_prepare(self, device_bbox):
if device_bbox is None:
w, h = self.window.get_size()
device_bbox = (0, 0, w, h)
#print 'device bbox', tuple(device_bbox)
gdk_clip_region = self.window.get_clip_region()
x, y, w, h = device_bbox
sparse = not gdk_clip_region.point_in(x + w / 2, y + h / 2)
cr = self.window.cairo_create()
# actually this is only neccessary if we are not answering an expose event
cr.rectangle(*device_bbox)
cr.clip()
# fill it all white, though not required in the most common case
if self.visualize_rendering:
# grey
tmp = random.random()
cr.set_source_rgb(tmp, tmp, tmp)
cr.paint()
# bye bye device coordinates
self.get_model_coordinates_cairo_context(cr)
# choose best mipmap
hq_zoom = False
if self.app and self.app.preferences['view.high_quality_zoom']:
hq_zoom = True
if hq_zoom:
# can cause a very clear slowdown on some hardware
# (we probably could avoid this by doing rendering differently)
mipmap_level = max(0, int(floor(log(1.0 / self.scale, 2))))
else:
mipmap_level = max(0, int(ceil(log(1 / self.scale, 2))))
# OPTIMIZE: if we would render tile scanlines, we could probably use the better one above...
mipmap_level = min(mipmap_level, tiledsurface.MAX_MIPMAP_LEVEL)
cr.scale(2**mipmap_level, 2**mipmap_level)
translation_only = self.is_translation_only()
# calculate the final model bbox with all the clipping above
x1, y1, x2, y2 = cr.clip_extents()
if not translation_only:
# Looks like cairo needs one extra pixel rendered for interpolation at the border.
# If we don't do this, we get dark stripe artefacts when panning while zoomed.
x1 -= 1
y1 -= 1
x2 += 1
y2 += 1
x1, y1 = int(floor(x1)), int(floor(y1))
x2, y2 = int(ceil(x2)), int(ceil(y2))
# alpha=True is just to get hardware acceleration, we don't
# actually use the alpha channel. Speedup factor 3 for
# ATI/Radeon Xorg driver (and hopefully others).
# https://bugs.freedesktop.org/show_bug.cgi?id=28670
surface = pixbufsurface.Surface(x1,
y1,
x2 - x1 + 1,
y2 - y1 + 1,
alpha=True)
del x1, y1, x2, y2, w, h
return cr, surface, sparse, mipmap_level, gdk_clip_region