View Issue Details

IDProjectCategoryView StatusLast Update
0024241LazarusLCLpublic2020-03-31 13:53
Reporterph4n70m Assigned To 
Status newResolutionopen 
Product Version1.0.8 
Summary0024241: TBitBtn do not display bitmap correctly
DescriptionWhen I add to project TBitBtn and set TBitmap from file on the form all looks fine. But in runtime bitmap doesn't display as it should be. I attached sample in the archive
Tagstbitmap, transparent
Fixed in Revision
Attached Files


related to 0036383 new 32 bit bitmaps will not draw transparently due to incomplete code. 
related to 0035585 new Writting on transparent Bitmap 
related to 0033793 new Imagelist Editor - non default transparency 
related to 0036490 resolvedOndrej Pokorny Bitmap transparency (mask) not respected by TMenuItem 
related to 0031556 new transparency not working when drawing a bitmap to a canvas 
related to 0011757 assignedMarc Weustink No PNG transparency in runtime 
related to 0027540 new TBitBtn Glyph show no correct in Runtime 
related to 0023823 new Bug painting 32bits tbitmaps on linux lazarus. 
related to 0022135 new Timage Canvas.Pixels[x,y] Transparent and some bit's 
related to 0018651 assignedFelipe Monteiro de Carvalho TrayIcon doesn't transfer transparent colour from bitmap to trayicon properly 



2013-04-07 16:21

reporter (346,793 bytes)

Bart Broersma

2020-02-12 23:05

developer   ~0121067

With Lazarus 2.1.0 r62605 (FPC 3.0.4 i386-win32-win32/win64) the program refuses to start.

C:\Users\Bart\LazarusProjecten\bugs\bitbtn>gdb project1
GNU gdb (GDB) 7.2
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "mingw32".
For bug reporting instructions, please see:
Reading symbols from C:\Users\Bart\LazarusProjecten\bugs\bitbtn/project1.exe...done.
(gdb) run
Starting program: C:\Users\Bart\LazarusProjecten\bugs\bitbtn/project1.exe
Error creating process C:\Users\Bart\LazarusProjecten\bugs\bitbtn/project1.exe, (error 740).

Bart Broersma

2020-02-12 23:33

developer   ~0121070

Last edited: 2020-02-12 23:41

View 2 revisions

Even if I remove the bitbutton (so now only an empty form) the program refuses to run.

ETA: Never mind. The project has UI access checken on.
After unchecking this at least it runs.

IIRC then the bottom right pixel of a bitmap is used to define what color is transparent, which explains how it looks at runtime.

Juha Manninen

2020-02-17 19:52

developer   ~0121148

I tested on Linux + QT5. I don't know exactly how the image should look like.
In the glyph editor it is a blue wide band.
At design time on the button it is grey.
At run time on the button it is blue again but fills the whole button.
Graphics experts please look at this.

jamie philbrook

2020-02-17 22:34

reporter   ~0121152

@bart, it should be the bottom left that defines the color for auto transparency .

 I haven't looked at the bitmap but if it is a 32 bit image then there is a problem in the Tbitmap, the transparent does not work..

Issue History

Date Modified Username Field Change
2013-04-07 16:21 ph4n70m New Issue
2013-04-07 16:21 ph4n70m File Added:
2013-04-07 16:22 ph4n70m Tag Attached: tbitmap
2020-02-12 23:05 Bart Broersma Note Added: 0121067
2020-02-12 23:33 Bart Broersma Note Added: 0121070
2020-02-12 23:41 Bart Broersma Note Edited: 0121070 View Revisions
2020-02-17 19:52 Juha Manninen Note Added: 0121148
2020-02-17 22:34 jamie philbrook Note Added: 0121152
2020-03-31 10:02 Juha Manninen Relationship added related to 0036383
2020-03-31 10:06 Juha Manninen Relationship added related to 0035585
2020-03-31 10:22 Juha Manninen Relationship added related to 0033793
2020-03-31 10:29 Juha Manninen Relationship added related to 0036490
2020-03-31 10:37 Juha Manninen Relationship added related to 0031556
2020-03-31 10:55 Juha Manninen Relationship added related to 0011757
2020-03-31 10:59 Juha Manninen Relationship added related to 0027540
2020-03-31 11:04 Juha Manninen Relationship added related to 0023823
2020-03-31 11:06 Juha Manninen Relationship added related to 0022135
2020-03-31 11:10 Juha Manninen Relationship added related to 0018651
2020-03-31 13:53 Juha Manninen Tag Attached: transparent