Continuous Digital Zooming

This tutorial describes how to perform continuous digital zooming using the Ecam API.


For advanced camera settings, the continuous digital zooming API provides a greater control over continuous zoom by allowing you to specify the speed and acceleration of each continuous zoom operation. The minimum speed for zooming is zero and the minimum acceleration is a negative value (which means deceleration).

For continuous zooming, you need to provide a concrete implementation of MCameraContinuousZoom.


Before you start you should understand the following topics:

  • Overview of the advanced Camera settings functionality.

  • Tutorial of the advanced Camera settings functionality.


  1. Call CCameraAdvancedSettings::NewL(CCamera&) to create a CCameraAdvancedSettings object.
  2. Call CCameraAdvancedSettings::GetSupportedContinuousZoomTypeL(TUint&) to retrieve supported continuous zoom options for CCameraAdvancedSettings.
  3. Call CCameraAdvancedSettings::CreateContinuousZoomL(MContinuousZoomObserver&, TContinuousZoomType, CCameraContinuousZoom*&) to create a continuous zoom object.
  4. Call CCameraContinuousZoom::GetContinuousZoomSupportInfoL(CCameraAdvancedSettings::TContinuousZoomSupportInfo&) to retrieve information about the supported settings related to continuous zoom.
  5. Call CCameraAdvancedSettings::StartContinuousZoomL(CCameraAdvancedSettings::TContinuousZoomParameters) to start the continuous zoom operation.
  6. Call the CCameraContinuousZoom::ContinuousZoomProgress(CCameraContinuousZoom&, TInt, TInt) function when a new zoom factor has achieved during the current continuous zoom operation.
  7. Call the CCameraAdvancedSettings::GetContinuousZoomId (TInt aZoomId) function when you use more than one continuous zoom operation. This function is used to retrieve a unique ID which you can use to determine the callback function (like ContinuousZoomProgress() or ContinuousZoomCompleted()) is associated with which continuous zoom object.
  8. Call CCameraContinuousZoom::ContinuousZoomCompleted() to inform you that the continuous zoom function has either completed successfully or to report an error that has caused the operation to fail. Note: This callback function does not actually stop the continuous zoom.
  9. Call CCameraAdvancedSettings::StopContinuousZoom() to stop continuous zooming, if the continuous zoom function has not already completed.


The following example shows you how to perform continuous digital zooming using the Ecam API:

CCamera* camera;
MCameraObserver2* observer2;
Camera = CCamera::New2L(*observer2, 0);
CCamera::CCameraAdvancedSettings* settings = CCamera::CCameraAdvancedSettings::NewL(*camera);
TUint supportedContinuousZoomType;
CCamera::CCameraAdvancedSettings::TContinuousZoomType continuousZoomType =
MContinuousZoomObserver* continuousZoomObserver;     
CCamera::CCameraContinuousZoom* continuousZoom = NULL;
settings->CreateContinuousZoomL(*continuousZoomObserver, continuousZoomType, continuousZoom);
CCamera::CCameraAdvancedSettings::TContinuousZoomSupportInfo info;
CCamera::CCameraAdvancedSettings::TContinuousZoomParameters param;
param.iContinuousZoomType = continuousZoomType;
param.iContinuousZoomAcceleration = 0;
param.iContinuousZoomSpeed = 1;
param.iContinuousZoomLimit = 5;
param.iZoomDirection = CCamera::CCameraAdvancedSettings::EZoomDirectionWide;

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