I`m using Delphi XE3. When using the custom styles (e.g. Carbon) that are available since Delphi XE2, there is a visible white flickering when moving the mouse over the borders of the TComboBoxEx control (MouseExit/Enter).
Steps to reproduce: Create a new VCL Forms app, drop a TComboBoxEx on the form, select e.g. Carbon in project options --> Application\Appearance and start the application
Is this a known problem/bug and is any solution known?
Thank you
This Border flicker issue is not the product of using Delphi VCL Styles.
(The same problem can be observed without using VCL styles)
The culprit here is the Desktop Window Manager which is an essential part of Windows Visual Styles and Themes.
The reason why you are seeing this issue and others may not, is because you have at some point changed the default Windows Theme (aero theme) or you've changed a specific Visual effect property of your selected theme.
You perhaps also have intentionally or unintentionally disabled the Desktop Window Manager since it runs as a Windows service.
To be more exact, the issue is resolved if you enable the Desktop composition feature.
This feature is only available in Aero themes(default) but not in Basic or Classic, tho sometimes it can appear to be available even when it is not.
Control Panel --> System --> Advanced System Settings --> Advanced --> Performance Settings --> Visual Effects
When desktop composition is enabled, individual windows no longer draw
directly to the screen or primary display device as they did in
previous versions of Windows. Instead, their drawing is redirected to
off-screen surfaces in video memory, which are then rendered into a
desktop image and presented on the display.
As you might have guessed, the functionality of this function is to basically act as a Buffer which in a very neat way explains the border flickering when this option is turned off.
Important Fact
Desktop composition feature can only be enabled if your current theme is an Aero theme and using Windows Visual Styles.(It is by default enabled for every Aero Theme)
Visual Styles are enabled by default in Aero Themes, you can check that it is enabled by making sure that the Use Visual Styles on Windows feature is enabled in the Performance Settings. When the Classic or Basic Themes are in effect the desktop composition feature is never in play and cannot be enabled. (Classic theme has been deprecated since Windows 8)
Sometimes in Windows 7, the Desktop composition feature can show itself in the Performance Options even when using a Basic or Classic Theme but do not be fooled, this is an internal bug.
Steps to reproduce this bug :
Start With default Windows Aero Theme
Go into Performance Settings as described above
Uncheck the Desktop composition from the list
Mouse over the border of TComboBoxEx, it should now be flickering as
you enter/leave.
But what happens if I uncheck Use Visual Styles on Windows checkbox? Why does this solve the flickering issue?
This will cause the Desktop Window Manager(DWM) to disable themes all together for all Windows Controls. What this means is that controls will be drawn using an older rendering style as oppose to using the newer Aero rendering style.
You can turn off Visual Styles for individual controls without turning it off globally with the following method SetWindowTheme(Handle, nil, nil)
This is also why the flickering issue for TComboBoxEx border is resolved when Visual Styles are disabled.
It's also worth mentioning that since Windows 8 you cannot disable Visual Styles anymore because as I said the Classic theme is deprecated.
Regarding the solution, I don't think you've got much of a choice really. Given how much freedom is left to the user when it comes to modifying the visual effects of Windows themes, this sort of thing is bound to happen. At least you can be certain that this issue does not happen on the default Windows Theme.
Related
Running windows 10 21H2. Just upgraded to Delphi 11.2 (from 11.1).
Speedbuttons (with Flat=False) do not show the button rectangle at design time. It does appear at runtime.
Most/all of our VCL projects have an empty style name. I have noticed that if I set the Stylename for the button (or even the form), then it shows normally. But is this the best way of handling it? Is there a global setting somewhere that can restore "normal" behaviour?
In 11.2 the Form Designer Options have a new option Mimic the system style, which is active by default. Disabling that should solve your problem.
Form Designer Options
As per my previous question (Delphi 6 support for toolbar and menu icons with alpha channel transparency), we are updating a legacy application developed in Delphi 6 to support Windows Visual Themes by including a Manifest. This has worked well and we have the majority of controls adopting the Windows visual theme correctly.
However, we do have a problem with TDateTimePicker behaving in a slightly odd manner. We have the form colour set to white (RGB 255/255/255) and the input box for TDateTimePicker is not visible on the form until it is clicked into and has an entry in it. Please see screenshots below:
Changing the form colour to grey, we can see that the box is there when not selected, it just has no border drawn around it:
We have been unable to find a property that will change this behaviour. Can anyone shed some light on why this might be occurring, what property needs to be changed, or another method we could possibly use to resolve it?
Standard Delphi controls (panels, buttons etc.) all have this bevel effect (white line on top and on the left) that gives them a 3D feel but today it makes them look old fashioned.
Is there a way to remove this "3D look" at least in Delphi 7?
Some controls have a Ctl3D property that you can turn off.
For a TPanel, you can also turn off its Bevel... properties.
What you really should do instead is enable Visual Styles in your app so it has a themed look on Windows XP and later. Delphi 7 did not natively support Visual Styles, but you can use Mike Lischke's XP Theme Manager component to handle that (it was incorporated directly into later VCL versions).
Have you seen this?
I have a little utility application (for easy load / test xml generation from CDS and/or DBGo), and I had put some buttons (the poorest button of all, TButton) to trigger some actions.
I never paid attention to appearance, because I'm the only one that uses it. So today I added a new button, and they appeared different from the others in designer - but not when running. It's just an copy and paste process (change the button name, caption and event - the rest is equal to the origin).
When I looked the other buttons have an grey gradient and round corners, the button I copied and pasted not (just a bare rectangle). When running all buttons where just bare rectangles.
So I discovered that on designer, W7 and delphi are applying themes. On running, they are obeying the Project/Options/Application/Enable runtime themes flag.
This is annoying. There's a way to make Delphi doing that obeying the project options flag on forms designer?
(Or even manually if is not possible to automate that)?
EDIT:
The toolbars on the form are from CNWizards ;-)
EDIT II:
Apart of disabling themes for the IDE executable, all buttons get themed equally if the form (or project) is reloaded. But it's really weird.
If you want to enable/disable themes in the IDE, then open the properties of bds.exe, select the 'Compatibility' tab, and make sure that the 'Disable visual themes' checkbox is unchecked/checked.
Programs that you run from the IDE will inherit the compatibility settings of the IDE.
Delphi IDE itself is an application and the way the designer draw the form is using the setting for the IDE application (delphi32.exe or bds.exe's compatibility settings) so the answer is no. The default behaviour is different between IDE versions, for eg. the opposite behaviour (not drawing themed) happened in past.
I've noticed that when I use TRibbon control that comes with Delphi 2010, it works flawlessly on my Windows 7 system. However, the application has some weird painting issues on a Windows XP system with the "classic theme" (I haven't tried the playschool theme).
I know there are other Ribbon components available from DevExpress and TMS Software, however purchasing a 3rd party control is not an option for this project.
Has anyone had this issue, or know of a solution?
Most likely because Windows 7 uses "Desktop Compositing", which essentially means that a component is drawn to an off-screen bitmap and then copied onto the display. In XP, a component typically draws directly onto the display (which can cause flicker if the component first erases what's there and draws over the "clean slate").
Delphi supports double-buffering, which accomplishes the same thing. If you set the ribbon's DoubleBuffered property to True (in code, since it's not published) then that should avoid the flicker (at the cost of extra memory allocated and moved around when drawing)--I should say, however, that I haven't actually tried it with TRibbon.
Note that there is no additional overhead when running on Windows 7 (or Vista, for that matter) if you set DoubleBuffered to True. The VCL has code the skips the off-screen bitmap business when running on a version of Windows that does desktop compositing.
Most likely this is a bug in the TRibbon code, the Microsoft ribbon renders perfect in both XP and Win7.
If you change your XP theme does the Minimise button shown in the image change to reflect your theme change? If this is the case the Ribbon code has probably been optimised for Vista and 7 and not been developed to run perfectly under XP.
You cant really resolve it unless you can modify the TRibbon code.