It displays a picture, which the user can rotate by pressing it with two fingers and rotating them. The image rotates in the direction that your fingers are pointing. The image rotates to the right when the fingers are rotated to the right. The image rotates to the left when the fingers are rotated to the left.
Table of Contents
Location
You can find the ImageRotation sample project at:
- Start | Programs | Embarcadero RAD Studio Sydney | Samples and then navigate to:
Object PascalMobile SnippetsInteractiveGesturesImageRotationCPPMobile SnippetsInteractiveGesturesImageRotation
- Subversion Repository:
- You can find Delphi and C++ code samples in GitHub Repositories. Search by name into the samples repositories according to your RAD Studio version.
How to Use the Sample
- Navigate to one of the locations given above and open:
- Delphi: ImageRotation.dproj.
- C++: ImageRotation.cbproj.
- Select the target platform, iOS and Android supported.
- Press F9 or choose Run > Run.
- Press the picture with two fingers and rotate them to see how the image rotates.
Files
| File in Delphi | File in C++ | Contains |
|---|---|---|
| ImageRotation.dproj | ImageRotation.cbproj | The project itself. |
| ImageRotationU.fmx | ImageRotationU.fmx | The main form where the components are located. |
| ImageRotationU.pas | ImageRotationPCH.h, ImageRotation.cpp | Used to define and implement the sample. |
| Information.txt | Information.txt | Further information about the sample. |
Implementation
- The sample uses TImage to display and define a 2D image component.
- The property RotationAngle is used to specify the amount (in degrees) by which the image is rotated from the x-axis.
- The sample uses the TGestureManager class to manage all the touch and gesturing functionalities of the application.
- The TGestureEventInfo describes a gesture event. It is a record that contains information about a gesture event. The TGestureEvent type passes a TGestureEventInfo record to the user code.
The sample shows a picture. When the user presses the picture with two fingers, the TGestureEventInfo detects a gesture event. If the user rotates the fingers, the sample calculates the rotation angle in order to rotate the image with the same angle.
The link below will guide you to the original post of Embarcadero:
http://docwiki.embarcadero.com/CodeExamples/Sydney/en/FMX.ImageRotation_Sample
Do you want to quickly rotate an image with Gestures for iOS and Android? Try the Cross-Platform Development tool, which will assist you in developing apps in the Delphi or C++ environments.