FMX.ImageZoom Sample

This sample uses the TGestureManager class to demonstrate how to zoom an image.

Location

You can find the ImageZoom sample project at:

• Start | Programs | Embarcadero RAD Studio 10 Seattle | Samples and then navigate to:
  • Object Pascal\Mobile Snippets\InteractiveGestures\ImageZoom
  • CPP\Mobile Snippets\InteractiveGestures\ImageZoom
• Subversion Repository:
  • Delphi: http://sourceforge.net/p/radstudiodemos/code/HEAD/tree/branches/RADStudio_Seattle/Object%20Pascal/Mobile%20Snippets/InteractiveGestures/ImageZoom
  • C++: http://sourceforge.net/p/radstudiodemos/code/HEAD/tree/branches/RADStudio_Seattle/CPP/Mobile%20Snippets/InteractiveGestures/ImageZoom

Description

The ImageZoom sample demonstrates how to zoom an image on an iOS or Android device. The sample provides a picture and the user can zoom the picture by pinching it.

How to Use the Sample

1. Navigate to one of the locations given above and open:
   • Delphi: ImageZoom.dproj.
   • C++: ImageZoom.cbproj.
2. Select the target platform, iOS and Android supported.
3. Press F9 or choose Run > Run.
4. Pinch the picture to see how it zooms.

Files

File in Delphi	File in C++	Contains
ImageZoom.dproj	ImageZoom.cbproj	The project itself.
ImageZoomU.fmx	ImageZoomU.fmx	The main form where the components are located.
ImageZoomU.pas	ImageZoomPCH.h, ImageZoom.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 properties TImage.Position, TImage.Width and TImage.Height are used to specify the position and size of the image.
• 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. The sample uses the field GestureID of the TGestureEventInfo to identify a zoom gesture. When TGestureEventInfo identifies a zoom gesture, the sample uses the TImage.Position, TImage.Width and TImage.Height properties to zoom the picture.

Uses

• FMX.Objects.TImage
• FMX.Objects.TImage.Position
• FMX.Objects.TImage.Width
• FMX.Objects.TImage.Height
• FMX.Gestures.TGestureManager
• FMX.Types.TGestureEventInfo

See Also

• Images
• Mobile Tutorial: Taking and Sharing Pictures (iOS and Android)
• Gesturing Overview
• Using Gesturing in Your Applications

Samples

• VCL.ImageProc_Sample
• FMX.ImageRotation_Sample
• FMX.TapAndHold_Sample
• FMX.AccessCameraApp Sample