def write_image(
feedback,
tex_layer,
tex_pixel_size,
destination_crs,
destination_extent,
filepath,
imagetype,
):
"""
Save current QGIS canvas to image file.
"""
feedback.pushInfo("Rendering texture image (timeout in 30s)...")
project = QgsProject.instance()
# Get extent size in meters
d = QgsDistanceArea()
d.setSourceCrs(
crs=destination_crs, context=QgsProject.instance().transformContext()
)
p00, p10, p01 = (
QgsPointXY(destination_extent.xMinimum(), destination_extent.yMinimum()),
QgsPointXY(destination_extent.xMaximum(), destination_extent.yMinimum()),
QgsPointXY(destination_extent.xMinimum(), destination_extent.yMaximum()),
)
wm = d.measureLine(p00, p10) # euclidean dist, extent width in m
hm = d.measureLine(p00, p01) # euclidean dist, extent height in m
# Image settings and texture layer choice
settings = QgsMapSettings() # build settings
settings.setDestinationCrs(destination_crs) # set output crs
settings.setExtent(destination_extent) # in destination_crs
if tex_layer:
layers = (tex_layer,) # chosen texture layer
else:
canvas = iface.mapCanvas()
layers = canvas.layers() # get visible layers
wpix = int(wm / tex_pixel_size)
hpix = int(hm / tex_pixel_size)
settings.setOutputSize(QSize(wpix, hpix))
settings.setLayers(layers)
feedback.pushInfo(
f"Requested texture size: {wm:.2f}x{hm:.2f} m, {wpix}x{hpix} pixels."
)
# Render and save image
render = QgsMapRendererParallelJob(settings)
render.start()
t0 = time.time()
while render.isActive():
dt = time.time() - t0
QCoreApplication.processEvents()
if feedback.isCanceled():
render.cancelWithoutBlocking()
return
if dt >= 30.0:
render.cancelWithoutBlocking()
feedback.reportError("Render timed out, no texture saved.")
return
image = render.renderedImage()
try:
image.save(filepath, imagetype)
except IOError:
raise QgsProcessingException(
f"Texture not writable to <{filepath}>, cannot proceed."
)
feedback.pushInfo(f"Texture saved in {dt:.2f} seconds.")
def write_texture(
feedback,
tex_layer,
tex_extent,
tex_pixel_size,
utm_crs, # destination_crs
filepath,
imagetype,
):
"""
Crop and save texture to image file.
"""
# Calc tex_extent size in meters (it is in utm)
tex_extent_xm = tex_extent.xMaximum() - tex_extent.xMinimum()
tex_extent_ym = tex_extent.yMaximum() - tex_extent.yMinimum()
# Calc tex_extent size in pixels
tex_extent_xpix = int(tex_extent_xm / tex_pixel_size)
tex_extent_ypix = int(tex_extent_ym / tex_pixel_size)
# Choose exporting layers
if tex_layer: # use user tex layer
layers = (tex_layer,)
else: # no user tex layer, use map canvas
canvas = iface.mapCanvas()
layers = canvas.layers()
# Image settings and texture layer choice
settings = QgsMapSettings() # build settings
settings.setDestinationCrs(utm_crs) # set output crs
settings.setExtent(tex_extent) # in utm_crs
settings.setOutputSize(QSize(tex_extent_xpix, tex_extent_ypix))
settings.setLayers(layers)
feedback.pushInfo(
f"Texture size: {tex_extent_xpix} x {tex_extent_ypix} pixels, {tex_extent_xm:.1f} x {tex_extent_ym:.1f} meters"
)
# Render and save image
render = QgsMapRendererParallelJob(settings)
render.start()
t0 = time.time()
while render.isActive():
dt = time.time() - t0
QCoreApplication.processEvents()
if feedback.isCanceled():
render.cancelWithoutBlocking()
return
if dt >= 30.0:
render.cancelWithoutBlocking()
feedback.reportError("Texture render timed out, no texture saved.")
return
image = render.renderedImage()
try:
image.save(filepath, imagetype)
except IOError:
raise QgsProcessingException(
f"Texture not writable to <{filepath}>, cannot proceed."
)
feedback.pushInfo(f"Saved (in {dt:.2f} s): <{filepath}>")
