Rotate VCL components in Delphi XE2

Question

Now I adapt my app for tablet PC. I ask how can I fixate form when the screen was rotated. Good people says that I must adapt my app for portrait orientation and they're right.

Some forms is very specific and it's very hard (maybe impossible) to re-design they for portrait orientation. So I think I can create a illusion that my app works only in landscape orientation.

That's why I need rotate standard VCL components in Delphi XE2. For example for standard memo I need write text not only from left to right (or right to left) and from up to down (and from down to up).

Also I need rotate button. Now I use standard TButton and TRxSpeedButton.

1. I think enough to rotate the text for TButton but I don't know how I can do this?

2. In case of TRxSpeedButton I use glyphs. In theory maybe I can override canvas and change pic. Another way is create 2 buttons (one for portrait orientation, one for landscape. Each one will have their special glyph) and change their visibility. But I don't like 2nd variant because in this case exe file will be very plump, I don't like plump exe))

Thanks for advises.

Answer 1

One way that might work for you would be to use the PaintTo method of various controls. Have them paint their fully drawn image onto a bitmap and then rotate the bitmap by 90 degrees to get the portrait versus landscape effect. Then draw that image on the canvas of your form in its OnPaint method (you would want to make the actual controls invisible when in the portrait mode, showing only your painted and rotated bitmaps.)

There are some controls (like TRichEdit) whose PaintTo Method doesn't work correctly, though. So this may be of limited use for you. Another way is to grab a screen capture of the entire client area of the form on the desktop and then rotate and display that. that works even with TRichEdit...

Answer 2

You've no realistic chance of making this work using standard VCL controls. VCL controls don't have a mode that allows them to be rotated through 90 degrees. I see no easy prospect for making any control that displays text do so rotated. That's just text output. What about text input? There's also the issue of shadows and 3D effects which are based on a specific orientation. The list goes on and on.

In my view, if you want to make this work well you'll almost certainly need to write an entire GUI framework from scratch.

Whilst it is clear possible to do this it doesn't seem like a realistic choice when set aside the alternative of making your app work in both portrait and landscape orientations.

Answer 3

You have no chance with fake landscape approach.

There are three solutions for your problem:

1. Best one - make your application work with any screen size / orientation combination. This is the Windows way.

2. If your application "must" work in landscape mode, inform users when you detect wrong orientation, that application only functions in landscape mode. Show either message box, or special form with message that cannot be missed, while you hide your other forms, or something like that.

3. Lock device in landscape mode, like described in How to prevent the screen from automatically rotating on a tablet? But you should know that this is not the way Windows are meant to be used in Desktop mode.

Answer 4

The VCL was not built for this, so I dont really see that happening without major work done to the presentation layer of the RTL.

The have been skinning engines that were capable of this, but they essentially patched the RTL and took over rendering. Rotation data was held in a lookup table for each control that you had to set separately from the actual class.

If Delphi had support for partial classes like Smart Pascal does, then perhaps (if the architecture allowed it) this could be postfixed. But as of writing the VCL is simply not made for this. I am writing a tweening library as I type this, so I have looked into this.