unit PAIEImageTrimming;

interface

uses
  ImageEnProc, ImageEnView, iexBitmaps, Vcl.Graphics, Winapi.Windows, hyieutils, hyiedefs;

type
  TIEBitmapHelper = class helper for TIEBitmap
    function Trim: TIEBitmap;
  private
    function FindMostCommonEdgeColor: TRGB;
    function IsRowUniform(Y: Integer; Color: TRGB): Boolean;
    function IsColumnUniform(X: Integer; Color: TRGB): Boolean;
    function FindTrimRect: TRect;
  end;

implementation

uses
  System.Classes, System.SysUtils;

function TIEBitmapHelper.FindMostCommonEdgeColor: TRGB;
var
  TopLeftPixel, BottomRightPixel: TRGB;
begin
  TopLeftPixel := Self.Pixels[0, 0]; 
  BottomRightPixel := Self.Pixels[Self.Width - 1, Self.Height - 1]; 
  // Assuming the top left pixel as the most common color for simplicity
  Result := TopLeftPixel;
end;

function TIEBitmapHelper.IsRowUniform(Y: Integer; Color: TRGB): Boolean;
var
  X: Integer;
  CurrentColor: TRGB;
begin
  for X := 0 to Self.Width - 1 do
  begin
    CurrentColor := Self.Pixels[X, Y]; 
    if not CompareMem(@CurrentColor, @Color, SizeOf(TRGB)) then
      Exit(False);
  end;
  Result := True;
end;

function TIEBitmapHelper.IsColumnUniform(X: Integer; Color: TRGB): Boolean;
var
  Y: Integer;
  CurrentColor: TRGB;
begin
  for Y := 0 to Self.Height - 1 do
  begin
    CurrentColor := Self.Pixels[X, Y]; 
    if not CompareMem(@CurrentColor, @Color, SizeOf(TRGB)) then
      Exit(False);
  end;
  Result := True;
end;

function TIEBitmapHelper.FindTrimRect: TRect;
var
  x, y: Integer;
  MostCommonEdgeColor: TRGB;
begin
  MostCommonEdgeColor := FindMostCommonEdgeColor;
  Result := System.Classes.Rect(0, 0, Self.Width, Self.Height);

  // Find top edge
  y := 0;
  while (y < Self.Height) and IsRowUniform(y, MostCommonEdgeColor) do
    Inc(y);
  Result.Top := y;

  // Find bottom edge
  y := Self.Height - 1;
  while (y >= Result.Top) and IsRowUniform(y, MostCommonEdgeColor) do
    Dec(y);
  Result.Bottom := y + 1;

  // Find left edge
  x := 0;
  while (x < Self.Width) and IsColumnUniform(x, MostCommonEdgeColor) do
    Inc(x);
  Result.Left := x;

  // Find right edge
  x := Self.Width - 1;
  while (x >= Result.Left) and IsColumnUniform(x, MostCommonEdgeColor) do
    Dec(x);
  Result.Right := x + 1;
end;

function TIEBitmapHelper.Trim: TIEBitmap;
var
  TrimRect: TRect;
begin
  TrimRect := FindTrimRect;
  Result := TIEBitmap.Create;
  try
    Result.Assign(Self);
    Result.Crop(TrimRect.Left, TrimRect.Top, TrimRect.Right - TrimRect.Left, TrimRect.Bottom - TrimRect.Top);
  except
    Result.Free;
    raise;
  end;
end;

end.

bmp := bmp.Trim;