QCAD.org Forum

Hi, I"m new to the forum, but not to QCAD.
I have recently upgraded from an old QCAD version to version 6.5.2 and am encountering some difficulties with it that weren't a problem before.
OS is Mac OS, version 14.1.2.

My question is similar to here: https://www.qcad.org/rsforum/viewtopic.php?t=7769 but subtly different, so apologies if this new post is in the wrong place.

When I import a bitmap image and then start to trace it I generate a new CAD drawing over the buildings, roads etc from my photograph/bitmap. However when I click off the main lines and then hover over the bitmap, all my lines disappear each time the cursor puts attention on the main bitmap. This makes it difficult to work over my photograph layer. This wasn't an issue with my previous QCAD version and is quite frustrating.

I'd be really grateful for any help,

Thanks

Féidhlim

The reason:

QCAD displays the currently highlighted entity that is nearest to the mouse cursor in front, so you cannot accidentally select something you cannot see. This has not changed in recent versions.

The solution:

Put the image on a separate layer and lock that layer, making the bitmap not selectable.
You might also want to change the fade property of the image to make it a bit transparent which works well for tracing.

Many thanks Andrew, that was a really quick reply!

I was using Version 4.8.6 before and it didn't do that. For some reason that version highlights lines, but not the bitmap imports, which makes for much easier drawing over existing images.

Your method works; thank you for that work around - but it's still clunkier than the previous QCAD version that I was using before.

Any possibility to revert to the older feature?

Thanks,

Féidhlim

You can disable highlighting of entities completely under:
Edit > Application Preferences > Graphics View > Behavior > Highlight entity within range (untick)

The behaviour is desired when working with overlapping bitmaps. A separate preference might be added for bitmaps.

Thanks for that. I still preferred the older version of QCAD in that instance where bitmaps weren't highlighted by hovering over them at all, making overlain lines easier to read during work.

QCAD 3.29.4 is now available which has a new preference for this (images are not raised by default).

I would still strongly recommend to put background images on a locked layer for tracing to prevent accidental selection or modification.

Thanks Andrew, much appreciated.

andrew wrote: ↑

Fri Feb 02, 2024 11:19 am

The reason:

QCAD displays the currently highlighted entity that is nearest to the mouse cursor in front, so you cannot accidentally select something you cannot see. This has not changed in recent versions.

The solution:

Put the image on a separate layer and lock that layer, making the bitmap not selectable.
You might also want to change the fade property of the image to make it a bit transparent which works well for tracing.

Hi Andrew,

I locked the bitmap (it is not selectable) but it is always in the front if I move the mouse over the drawing. What do I wrong?
My installation QCad 3.32 on a Mac with a M4 pro and OSX Sequoia

AnobiumPunctatum wrote: ↑

Sun May 18, 2025 12:29 pm

I locked the bitmap (it is not selectable) but it is always in the front if I move the mouse over the drawing.

First, one can not lock an entity, one can lock the layer where it lives on.

Import or move your bitmap entity onto a dedicated layer an lock this layer afterwards.
Entities on locked layer can not be selected and thus not be highlighted.

By default selectable entities within range are highlighted.
This standard behavior has changed a little for bitmap entities in recent releases of QCAD.
There is now a bitmap exclusive preference under:
Menu Edit .. Application preferences .. Graphics View .. Behavior .. Highlight (and raise) images within range

You now have 2 options:
- Or on a locked layer.
- Or raised + highlighted or not when in range by preference.

Regards,
CVH

First, one can not lock an entity, one can lock the layer where it lives on.

That's exactly what I mean.

Import or move your bitmap entity onto a dedicated layer an lock this layer afterwards.
Entities on locked layer can not be selected and thus not be highlighted.

By default selectable entities within range are highlighted.
This standard behavior has changed a little for bitmap entities in recent releases of QCAD.
There is now a bitmap exclusive preference under:
Menu Edit .. Application preferences .. Graphics View .. Behavior .. Highlight (and raise) images within range

Sorry to say, but this does not work on my system. It does not matter if I check or uncheck the checkbox, if I lock or unlock the layer, the behavior is always the same.
The only change, which helps is to uncheck the checkbox "Objekte in Reichweite hervorheben". But in general I like the feature.

I have my bitmaps on different sublayers organized. Is it possible that this is the base for my problem?

Kind regards
Christian

AnobiumPunctatum wrote: ↑

Mon May 19, 2025 5:45 pm

I have my bitmaps on different sublayers organized. Is it possible that this is the base for my problem?

The locked state is inherited from the parent layer.
Or it can be set for the sub-layer individually.
This is functional for v3.32.2.0 installed on Windows 7 32bit.

AnobiumPunctatum wrote: ↑

Mon May 19, 2025 5:45 pm

Sorry to say, but this does not work on my system. It does not matter if I check or uncheck the checkbox, if I lock or unlock the layer, the behavior is always the same.

Unable to replicate that on my system.
The bitmap preference can be changed on the fly, locked or not too.
Both have the desired effect.

Your best option is to report this as a Mac related bug on QCAD Bugtracker.
There you need to have or apply for an account, what it is unrelated to your forum account.

An example file that reflects your layer and entity construction can be handy.
Remember to include any bitmap file(s) because these are not stored in the drawing file.

Regards,
CVH

Thanks, I will have a look at the bug tracker and prepare the report at the weekend.

@CVH

Thanks for your assistance. I found the error and must say, it was my mistake. I put the images in a block and haven't seen that the block was placed on a wrong layer. After fixing this the behavior is exactly as described from you.

Hi,
This thus reminds me of what is explained in FS#2629 except that it is the locked nature.

On the other hand, a Block Reference is itself an entity and that falls in the category 'Highlight entity within range'.
'Highlight (and raise) images within range' does not apply to the block reference, since it is not a bitmap entity.
Even if its only content is a bitmap.
To ensure that the Block Reference is not highlighted it must be placed on a locked layer.

I see no reason to place only a bitmap in a Block Reference except for including it in various places, scales and orientations in Model_Space.
The bitmap exclusive preference for highlighting is made dysfunctional except when editing the content of the Block in question.

Because a bitmap is not stored in the DXF/DWG I think you are better of with including bitmaps directly.
Several copies won't make the drawing file that much bigger and in memory that would also be the same.
Rendering several the same bitmaps or one bitmap in several places would probably be take the same time.

Regards,
CVH