TImageEnProc.JoinBitmaps

Declaration

function JoinBitmaps(Source1, Source2: TIEBitmap; JoinVertically: Boolean; BGColor: TColor = clWhite; StripOverlap: Boolean = False; MinEquality: Double = 0.99; Exhaustive: Boolean = False; Coverage: Double = 1.0): Integer;

Description

Replaces the content with two source images drawn side-by-side (or above and below if JoinVertically=True).
Both bitmaps must be ie24RGB.
If StripOverlap = True, then the result is the number of rows/colums that were cropped (if the result is 0 then no overlap could be found).

Parameter	Description
Source1, Source2	Specifies the two source images (either can be nil to specify this bitmap)
JoinVertically	If False, Source1 is drawn on the left and Source 2 on the right. If True, Source1 is drawn on the top and Source 2 on the bottom
BGColor	If one image is taller/wider than the other there will be background showing. Specify the color of the background fill, or clNone to fill with alpha
StripOverlap	If enabled, a check is performed to see if there is any overlapping pixels on the joining edge of the two images, and it is removed
MinEquality	If StripOverlap = True, this specifies the level of equality to look for when comparing the overlapping region (from 0.0 to 1.0, where 1.0 looks for an exact match). If you have difficulty finding an accurate value, enable the Exhaustive parameter, and specify a low value for MinEquality
Exhaustive	If StripOverlap = True, Exhaustive determines whether it checks every possibilities and returns the best one (Exhaustive=True) or just returns the first match that exceeds the specified MinEquality (Exhaustive=False). Exhaustive gives a much more accurate result, but will be much slower
Coverage	If StripOverlap = True, this specifies how extensively we check for overlap matching. This is used to speed up processing of very large images. For example, 1.0 means we check every row, 0.1 means we only check every tenth row, etc.

Note:
◼ You may specify the current bitmap for Source1 or Source2
◼ if StripOverlap = True the images must be the same width for a vertical join or the same height for a horizontal join
◼ Progress will only occur when StripOverlap true
◼ Undo is not saved
◼ Progress is not accurate as it terminates when a match is encountered. It will rarely reach 100% and will tend to slow as it progresses
◼ Also see TIEVisionStitcher which allows joining of multiple images with overlapped content

Demo

Demos\ImageEditing\EveryMethod\EveryMethod.dpr

Comparison

// Joining two bitmaps that are 300px wide with some overlapping content

// METHOD 1 - JOIN ONLY

// Join two images horizontally and display them (without checking for overlapping content)
bmpL := TIEBitmap.Create();
bmpR := TIEBitmap.Create();
bmpL.Read( 'D:\JoinBitmap_Left.png' );
bmpR.Read( 'D:\JoinBitmap_Right.png' );
ImageEnView1.Proc.JoinBitmaps( bmpL, bmpR, False, clNone );
bmpL.Free;
bmpR.Free;

// Result is 600px wide - Overlap remains

// METHOD 2 - NON-EXHAUSTIVE CHECKING FOR OVERLAP

// Join two images horizontally and display them (performing a non-exhaustive search for overlapping content)
bmpL := TIEBitmap.Create();
bmpR := TIEBitmap.Create();
bmpL.Read( 'D:\JoinBitmap_Left.png' );
bmpR.Read( 'D:\JoinBitmap_Right.png' );
ImageEnView1.Proc.JoinBitmaps( bmpL, bmpR, False, clNone, True, 0.99 );
bmpL.Free;
bmpR.Free;

// Result is 477px wide - Small amount of overlap remains

// METHOD 3 - EXHAUSTIVE CHECKING FOR OVERLAP

// Join two images horizontally and display them (performing an exhaustive search for overlapping content)
bmpL := TIEBitmap.Create();
bmpR := TIEBitmap.Create();
bmpL.Read( 'D:\JoinBitmap_Left.png' );
bmpR.Read( 'D:\JoinBitmap_Right.png' );
ImageEnView1.Proc.JoinBitmaps( bmpL, bmpR, False, clNone, True, 0.8, True );
bmpL.Free;
bmpR.Free;

// Result is 473px wide - Overlap is correctly removed

Examples

// Draw an image on the right of the current image (blank space will be transparent)
bmp := TIEBitmap.Create();
bmp.Read( 'D:\image2.png' );
ImageEnView1.Proc.JoinBitmaps( nil, bmp, False, clNone );
bmp.Free;

// Duplicate the current bitmap vertically
ImageEnView1.Proc.JoinBitmaps( nil, nil, True );

// Join two images removing any part of the image that is the same at the joining edge
// Exact matches only. Don't use exact matches for lossy formats like JPEG
ImageEnView3.Proc.JoinBitmaps( ImageEnView1.IEBitmap, ImageEnView2.IEBitmap, False, clWhite, True, 1.0 );

// Or perform an exhaustive search which gives the best result, but is much slower (because it checks every possibility)
// (You can specify a low value for MinEquality if Exhaustive is used)
ImageEnView3.Proc.JoinBitmaps( ImageEnView1.IEBitmap, ImageEnView2.IEBitmap, False, clWhite, True, 0.5, True );

// Quick joining of two images removing any part of the image that is the same at the joining edge
// This method only checks every 100th row so overlap detection may not be as accurate, but it is much faster
ImageEnView3.Proc.JoinBitmaps( ImageEnView1.IEBitmap, ImageEnView2.IEBitmap, False, clWhite, True, 0.98, False, 0.01 );

// Horizontally join 5 images that have overlapping joining edges
bmpIn := TIEBitmap.Create();
for i := 1 to 5 do
begin
  bmpIn.Read( 'D:\Join' + i.ToString + '.jpg' );
  if i = 1 then
    ImageEnView1.Assign( bmpIn )
  else
    ImageEnView1.Proc.JoinBitmaps( nil, bmpIn, False, clWhite, True, 0.997 );
end;
bmpIn .Free;

TImageEnProc.JoinBitmaps