Bug: Render with No Active Channels

[saloynton]

Split-view of thumbnails, missing images shown for images in dataset with no blue channels. Should have a space filler generated of correct size to preserve the layout.

• OMERO-merge-blue - Build # 157

This is due to the fact that the rendering Engine throws an exception if you turn off all the channels then try to render

i = conn.getObject("Image", 145)
pid = i.getPixelsId()
re = conn.createRenderingEngine()
re.lookupPixels(pid)
re.load()
pd = omero.romio.PlaneDef()
pd.z = 10
pd.t = 0
re.renderCompressed(pd)       # OK
re.setActive(0, False)              # This is a single-channel image
re.renderCompressed(pd) 

  File "/Users/will/Desktop/OMERO/dist/lib/python/omero_api_RenderingEngine_ice.py", line 326, in renderCompressed
    return _M_omero.api.RenderingEngine._op_renderCompressed.invoke(self, ((_def, ), _ctx))
omero.ApiUsageException: exception ::omero::ApiUsageException
{
    serverStackTrace = ome.conditions.ApiUsageException: No active channel bindings found.
	at omeis.providers.re.GreyScaleStrategy.findFirstActiveChannelBinding(GreyScaleStrategy.java:274)
	at omeis.providers.re.GreyScaleStrategy.renderAsPackedInt(GreyScaleStrategy.java:131)
	at omeis.providers.re.Renderer.renderAsPackedInt(Renderer.java:511)

[jburel]

This is an issue in Web

[jburel]

Scott:

what is the strategy you want to see implemented:

• if no channels, rendering engine turns one on. This could become annoying and breaks actual usage.
• clients check first or handle exception

Note that nothing stops the user to turn all the channels off.

[Will Moore <will@…>]

(In [4f0e6bde087f098866b20f417026d4b3e9690f65/ome.git] on branch develop) Split view center plugin uses webclient/render_image. See #8888

Switched from using webgateway/render_image since this doesn't use the webclient login_required
and can fail to set the correct group for looking up of images etc.

[wmoore]

Since this gives a black image: /webclient/render_image/1/15/0/?c=-1|70:314$0000FF,-2|396:1564$00FF00,-3|533:2798$FF0000,-4|445:4566$FF0000&m=c&p=normal&ia=0&q=0.9&zm=63&x=0&y=0
need to check what's different here vv code above.

[wmoore]

This appears to only affect single channel images.

E.g. this throws an exception for single channel images:

​http://localhost:8000/webclient/render_image/102/15/0/?c=-1

Some improved code below

from omero.gateway import BlitzGateway
import omero
from cStringIO import StringIO
import Image

conn = BlitzGateway('will', 'ome', host='localhost')
conn.connect()

i = conn.getObject("Image", 101)
pid = i.getPixelsId()
re = conn.createRenderingEngine()
sopts = {'omero.group':'-1'}
re.lookupPixels(pid, )
if not re.lookupRenderingDef(pid, sopts):
    re.resetDefaults(sopts)
    re.lookupRenderingDef(pid, sopts)
re.load()
pd = omero.romio.PlaneDef()
pd.z = 10
pd.t = 0
re.renderCompressed(pd)       # OK
re.setActive(0, False)              # This is a single-channel image
data = re.renderCompressed(pd)

i = StringIO(data)
rv = Image.open(i)
rv.show()

[cxallan]

Server side exception when there are no active channels is as follows:

 	

exception ::omero::ApiUsageException
{
    serverStackTrace = ome.conditions.ApiUsageException: No active channel bindings found.
	at omeis.providers.re.GreyScaleStrategy.findFirstActiveChannelBinding(GreyScaleStrategy.java:274)
	at omeis.providers.re.GreyScaleStrategy.renderAsPackedInt(GreyScaleStrategy.java:131)
	at omeis.providers.re.Renderer.renderAsPackedInt(Renderer.java:511)
	at ome.services.RenderingBean.renderAsPackedInt(RenderingBean.java:478)
	at ome.services.RenderingBean.renderCompressed(RenderingBean.java:532)
...

[cxallan]

Pull request:

• ​https://github.com/openmicroscopy/openmicroscopy/pull/360

[Chris Allan <callan@…>]

(In [23fb2e16b33158d971242edb1ca1da22fcb5de83/ome.git] on branch develop) Allow greyscale rendering when no channel binding active. (See #8888)

This commit ensures that like the HSBStrategy rendering with the
GreyScaleStrategy? while no channel binding is active is possible
and returns a completely blank image.

[Josh Moore <josh@…>]

(In [a201915b0fb65134ec9c7e826ebcc978390aa22d/ome.git] on branch develop) Merge pull request #360 from chris-allan/8888_no_active_channels

Allow greyscale rendering when no channel binding active. (See #8888)