TImageEnProc.PrepareTransitionBitmaps

Declaration

procedure PrepareTransitionBitmaps(StartBitmap, EndBitmap : TIEBitmap; Effect : TIETransitionType; iWidth : Integer = -1; iHeight : Integer = -1;
                                   BackgroundColor : TColor = -1; ResamplingFilter : TResampleFilter); overload;
procedure PrepareTransitionBitmaps(StartBitmap, EndBitmap : TBitmap; Effect : TIETransitionType; iWidth : Integer = -1; iHeight : Integer = -1;
                                   BackgroundColor : TColor = -1; ResamplingFilter : TResampleFilter); overload;

// Pan-Zoom overload
procedure PrepareTransitionBitmaps(StartBitmap, EndBitmap : TIEBitmap; Effect : TIETransitionType;
                                   StartRect, EndRect : TRect; RectMaintainAspectRatio : Boolean = True;
                                   iWidth : Integer = -1; iHeight : Integer = -1; bStretchSmall : Boolean = False;
                                   BackgroundColor : TColor = -1; ResamplingFilter : TResampleFilter;
                                   Smoothing: Integer = 255; Timing : TIETransitionTiming = iettLinear); overload;
procedure PrepareTransitionBitmaps(StartBitmap, EndBitmap : TBitmap; Effect : TIETransitionType;
                                   StartRect, EndRect : TRect; RectMaintainAspectRatio : Boolean = True;
                                   iWidth : Integer = -1; iHeight : Integer = -1; bStretchSmall : Boolean = False;
                                   BackgroundColor : TColor = -1; ResamplingFilter : TResampleFilter;
                                   Smoothing: Integer = 255; Timing : TIETransitionTiming = iettLinear); overload;

Description

Use with CreateTransitionBitmap to create a series of frames that transition from StartBitmap to EndBitmap.
The second overload is primarily used when creating a series of frames that show a Pan-Zoom from StartRect to EndRect for image StartBitmap.

Overload 1:

Parameter	Description
StartBitmap	The image that we transition from
EndBitmap	The image that we transition to
Effect	The desired transition effect
iWidth, iHeight	The size to create the transition bitmaps. If either of these are -1 then the size will be the larger of the two images in each dimension. Aspect Ratios will be maintained and any non-image area will be filled with BackgroundColor.
BackgroundColor	The color that will be used for blank frames or non-image area (if -1 then Background is used)
ResamplingFilter	The algorithm that is used to improve quality when resizing images

Overload 2 (Pan-Zoom effects)

Parameter	Description
StartBitmap	The image that we transition from
EndBitmap	The image that we transition to (NIL for a iettPanZoom transition)
Effect	The desired transition effect
StartRect	When using an iettPanZoom effect this is the portion of the image that is shown at the start
EndRect	When using an iettPanZoom effect this is the portion of the image that is shown at the end
RectMaintainAspectRatio	ImageEn will ensure that the starting and ending rects are automatically adjusted to ensure the resultant image has the correct aspect ratio (iettPanZoom only)
iWidth, iHeight	The size to create the transition bitmaps. If either of these are -1 then the size will be the larger of the two images in each dimension. Aspect Ratios will be maintained and any non-image area will be filled with BackgroundColor.
bStretchSmall	If the images are smaller than the transition bitmap size (iWidth x iHeight) should they be stretched to fit (which can lead to distortion).
BackgroundColor	The color that will be used for blank frames or non-image area (if -1 then Background is used)
ResamplingFilter	The algorithm that is used to improve quality when resizing images
Smoothing	In order to reduce the "jumpiness" of pan-zoom effects, transition frames can be alpha blended. A low value will improve smoothness, but increase blurriness. A high value will improve clarity, but increase jumpiness. Typical range is 64 - 196. 255 means no alpha blending (which is best when outputting to a bitmap)
Timing	The rate at which the transition progresses

To create Pan-Zoom transitions for an image call it as follows:

PrepareTransitionBitmaps(MyBitmap, nil, iettPanZoom, StartingRect, EndingRect);
CreateTransitionBitmap(TransitionLevel, MyPanZoomBitmap);

Demo

Demos\Multi\CreateTransitionFrames\CreateTransitionFrames.dpr

Examples

procedure TransitionFrameCreationExample;
var
  OldBitmap, NewBitmap, TransBitmap : TBitmap;
  I : Integer;
  TransLevel : Single;
begin
  OldBitmap := TBitmap.Create;
  NewBitmap := TBitmap.Create;
  TransBitmap := TBitmap.Create;
  try
    OldBitmap.LoadFromFile('C:\OldImage.bmp');
    NewBitmap.LoadFromFile('C:\NewImage.bmp');

    // Call PrepareTransitionBitmaps once
    ImageEnProc.PrepareTransitionBitmaps(OldBitmap, NewBitmap, iettCrossDissolve);

    for i := 1 to 9 do
    begin
      // Transition levels from 10% to 90%
      TransLevel := i * 10;

      // Call CreateTransitionBitmap for each required frame
      ImageEnProc.CreateTransitionBitmap(TransLevel, TransBitmap);
      TransBitmap.SaveToFile('C:\TransImage' + IntToStr(I) + '.bmp');
    end;
  finally
    OldBitmap.Free;
    NewBitmap.Free;
    TransBitmap.Free;
  end;
end;

procedure PanZoomFrameCreationExample(StartingRect, EndingRect : TRect);
var
  MyBitmap, PanZoomBitmap : TBitmap;
  I : Integer;
  TransLevel : Single;
begin
  MyBitmap := TBitmap.Create;
  PanZoomBitmap := TBitmap.Create;
  try
    MyBitmap.LoadFromFile('C:\MyImage.bmp');

    // Call PrepareTransitionBitmaps once
    ImageEnProc.PrepareTransitionBitmaps(MyBitmap, MyBitmap, iettPanZoom, StartingRect, EndingRect);

    for i := 0 to 10 do
    begin
      // Pan-Zoom Transitions from StartingRect (0%) to EndingRect (100%)
      TransLevel := i * 10;

      // Call CreateTransitionBitmap for each required frame
      ImageEnProc.CreateTransitionBitmap(TransLevel, PanZoomBitmap);
      PanZoomBitmap.SaveToFile('C:\PanZoomImage' + IntToStr(I) + '.bmp');
    end;
  finally
    MyBitmap.Free;
    PanZoomBitmap.Free;
  end;
end;

TImageEnProc.PrepareTransitionBitmaps