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| ///////////////////////////////////////////////////////////////////////////
// //
// Copyright (c) 2015 by Charta Software B.V. //
// All rights reserved //
// //
// Version: 1.7.0.83525 //
// Web site: https://pascal.chartasoftware.com/ //
// //
// This code and information are provided "as is" without warranty of //
// any kind. Dissemination of this information or reproduction of //
// this material is strictly forbidden unless prior written permission //
// is obtained from Charta Software B.V.. //
// //
///////////////////////////////////////////////////////////////////////////
unit Image.Raster;
interface
uses
Geometry._2d.Integer32.Rectangle,
Geometry._2d.Integer32.Size,
Image,
Integer._32,
Memory.Pointer;
type
TIntegerArray = array of TInteger32; // TODO: Deprecated type
PIntegerArray = ^TIntegerArray; // TODO: Deprecated type
TIntegerMatrix = array of TIntegerArray; // TODO: Deprecated type
TAlphaMode = (amOpaque, amNormal, amPremultiplied);
// TODO: TRasterImageComponents is the start of making sample representation flexible in raster image,
// however, most operations still expect a RGBA layout and should be implemented more flexibly
TRasterImageComponents = class(TObject)
public
function GetSampleSize(): TInteger32; virtual; abstract;
public
class var
Rgba: TRasterImageComponents;
Gray: TRasterImageComponents;
class constructor Create();
class destructor Destroy();
end;
TRasterImageRgba = class(TRasterImageComponents)
public
function GetSampleSize(): TInteger32; override;
end;
TRasterImageGray = class(TRasterImageComponents)
public
function GetSampleSize(): TInteger32; override;
end;
TRasterImage = class(TGraphicalImage)
private
FSize: TInteger32Size;
FComponents: TRasterImageComponents;
FAlphaMode: TAlphaMode;
protected
function GetScanLine(Row: TInteger32): TPointer; virtual; abstract;
function GetStride(): TInteger32; virtual; abstract;
public
constructor Create(const Size: TInteger32Size; Components: TRasterImageComponents; AlphaMode: TAlphaMode); reintroduce; virtual;
procedure FlipVertically();
function CreateSubimage(const Bounds: TInteger32Rectangle): TRasterImage;
procedure ApplyConvolution(Target: TRasterImage; Filter: TIntegerMatrix);
procedure CopyTo(Image: TRasterImage);
procedure ResizeTo(Target: TRasterImage);
function PremultiplyAlpha(): TRasterImage;
property Size: TInteger32Size read FSize;
property Components: TRasterImageComponents read FComponents;
property AlphaMode: TAlphaMode read FAlphaMode;
property ScanLine[Row: TInteger32]: TPointer read GetScanLine;
property Stride: TInteger32 read GetStride;
end;
implementation
uses
Color.Rgb,
Exception,
FloatingPoint._64,
Geometry._2d.FloatingPoint64.Size,
Image.Raster.Exception,
Image.Raster.Physical,
Image.Raster.Sub,
Mathematics;
{ TRasterImage }
procedure TRasterImage.ApplyConvolution(Target: TRasterImage; Filter: TIntegerMatrix);
var
i: TInteger32;
j: TInteger32;
k: TInteger32;
l: TInteger32;
SourceScanLines: array of PRgbColor;
SourceScanLine: PRgbColor;
TargetScanLine: PRgbColor;
FilterWidth: TInteger32;
FilterHeight: TInteger32;
FilterHalfWidth: TInteger32;
FilterHalfHeight: TInteger32;
FilterRow: PIntegerArray;
AppliedWeight: TInteger32;
StartX: TInteger32;
EndX: TInteger32;
StartY: TInteger32;
EndY: TInteger32;
Red: TInteger32;
Green: TInteger32;
Blue: TInteger32;
Pixel: PRgbColor;
Weight: TInteger32;
begin
if Components <> TRasterImageComponents.Rgba then
raise ERasterImage.Create('Operation currently only supports RGBA');
FilterWidth := Length(Filter[0]);
FilterHeight := Length(Filter);
FilterHalfWidth := FilterWidth div 2;
FilterHalfHeight := FilterHeight div 2;
SetLength(SourceScanLines, FilterHeight);
for i := 0 to Target.Size.Height - 1 do
begin
StartY := Maximum(0, i - FilterHalfHeight);
EndY := Minimum(i + FilterHeight - FilterHalfHeight - 1, Target.Size.Height - 1);
for k := StartY to EndY do
SourceScanLines[k - StartY] := ScanLine[k];
TargetScanLine := Target.ScanLine[i];
for j := 0 to Target.Size.Width - 1 do
begin
StartX := Maximum(0, j - FilterHalfWidth);
EndX := Minimum(j + FilterWidth - FilterHalfWidth - 1, Target.Size.Width - 1);
Red := 0;
Green := 0;
Blue := 0;
AppliedWeight := 0;
for k := StartY to EndY do
begin
SourceScanLine := SourceScanLines[k - StartY];
FilterRow := @Filter[k - i + FilterHalfHeight];
Pixel := SourceScanLine;
Inc(Pixel, StartX);
for l := StartX to EndX do
begin
Weight := FilterRow^[l - j + FilterHalfWidth];
Inc(Red, Weight * Pixel.Red);
Inc(Green, Weight * Pixel.Green);
Inc(Blue, Weight * Pixel.Blue);
Inc(AppliedWeight, Weight);
Inc(Pixel);
end;
end;
TargetScanLine.Red := Red div AppliedWeight;
TargetScanLine.Green := Green div AppliedWeight;
TargetScanLine.Blue := Blue div AppliedWeight;
Inc(TargetScanLine);
end;
end;
end;
procedure TRasterImage.ResizeTo(Target: TRasterImage);
var
i: TInteger32;
j: TInteger32;
SourceBottom: TInteger32;
TargetScanLine: PRgbColor;
SourceScanLine1: PRgbColor;
SourceScanLine2: PRgbColor;
Neighbor11: PRgbColor;
Neighbor12: PRgbColor;
Neighbor21: PRgbColor;
Neighbor22: PRgbColor;
SourceX: TFloatingPoint64;
SourceY: TFloatingPoint64;
FlooredX: TInteger32;
FlooredY: TInteger32;
Weight11: TFloatingPoint64;
Weight12: TFloatingPoint64;
Weight21: TFloatingPoint64;
Weight22: TFloatingPoint64;
DeltaX1: TFloatingPoint64;
DeltaX2: TFloatingPoint64;
DeltaY1: TFloatingPoint64;
DeltaY2: TFloatingPoint64;
TotalWeight: TFloatingPoint64;
Ratios: T2dFloatingPoint64Size;
// X: TFloatingPoint64;
// Y: TFloatingPoint64;
begin
if Components <> TRasterImageComponents.Rgba then
raise ERasterImage.Create('Operation currently only supports RGBA');
// http://en.wikipedia.org/wiki/Bilinear_interpolation
Ratios := T2dFloatingPoint64Size.New(Target.Size.Width / Size.Width, Target.Size.Height / Size.Height);
SourceBottom := Size.Height - 1;
for i := 0 to Target.Size.Height - 1 do
begin
TargetScanLine := Target.ScanLine[i];
SourceY := i / Ratios.Height;
FlooredY := RoundDown(SourceY);
DeltaY1 := SourceY - FlooredY;
DeltaY1 := DeltaY1 * DeltaY1;
DeltaY2 := FlooredY + 1 - SourceY;
DeltaY2 := DeltaY2 * DeltaY2;
SourceScanLine1 := ScanLine[FlooredY];
SourceScanLine2 := ScanLine[Minimum(FlooredY + 1, SourceBottom)];
for j := 0 to Target.Size.Width - 1 do
begin
SourceX := j / Ratios.Width;
FlooredX := RoundDown(SourceX);
Neighbor11 := SourceScanLine1; Inc(Neighbor11, FlooredX);
Neighbor21 := Neighbor11; Inc(Neighbor21);
Neighbor12 := SourceScanLine2; Inc(Neighbor12, FlooredX);
Neighbor22 := Neighbor12; Inc(Neighbor22);
DeltaX1 := SourceX - FlooredX;
DeltaX1 := DeltaX1 * DeltaX1;
DeltaX2 := FlooredX + 1 - SourceX;
DeltaX2 := DeltaX2 * DeltaX2;
// TODO: The factors 0.1 seem te prevent division by zero problems but do not seem to be the best solution
// TODO: Is this the proper weight function as defined by the specification of the algorithm? Wikipedia does not use a SquareRoot() function
// It seems like this interpolation function gives much smoother results than bilinear interpolation so we have to make a proper abstraction
// to allow for interpolation functions to be exchanged.
Weight11 := 1 / (SquareRoot(DeltaX1 + DeltaY1) + 0.1);
Weight21 := 1 / (SquareRoot(DeltaX2 + DeltaY1) + 0.1);
Weight12 := 1 / (SquareRoot(DeltaX1 + DeltaY2) + 0.1);
Weight22 := 1 / (SquareRoot(DeltaX2 + DeltaY2) + 0.1);
// TODO: The following lines try to apply the Bilinear interpolation function
// X := SourceX - FlooredX;
// Y := SourceY - FlooredY;
//
// Weight11 := (1 - X) * (1 - Y);
// Weight12 := X * (1 - Y);
// Weight21 := (1 - X) * Y;
// Weight22 := X * Y;
TotalWeight := Weight11 + Weight21 + Weight12 + Weight22;
TargetScanLine.Red := RoundToNearest(
(
Weight11 * Neighbor11.Red +
Weight21 * Neighbor21.Red +
Weight12 * Neighbor12.Red +
Weight22 * Neighbor22.Red
) / TotalWeight
);
TargetScanLine.Green := RoundToNearest(
(
Weight11 * Neighbor11.Green +
Weight21 * Neighbor21.Green +
Weight12 * Neighbor12.Green +
Weight22 * Neighbor22.Green
) / TotalWeight
);
TargetScanLine.Blue := RoundToNearest(
(
Weight11 * Neighbor11.Blue +
Weight21 * Neighbor21.Blue +
Weight12 * Neighbor12.Blue +
Weight22 * Neighbor22.Blue
) / TotalWeight
);
TargetScanLine.Alpha := RoundToNearest(
(
Weight11 * Neighbor11.Alpha +
Weight21 * Neighbor21.Alpha +
Weight12 * Neighbor12.Alpha +
Weight22 * Neighbor22.Alpha
) / TotalWeight
);
Inc(TargetScanLine);
end;
end;
end;
procedure TRasterImage.CopyTo(Image: TRasterImage);
var
i: TInteger32;
j: TInteger32;
Source: PRgbColor;
Target: PRgbColor;
begin
if Components <> TRasterImageComponents.Rgba then
raise ERasterImage.Create('Operation currently only supports RGBA');
for i := 0 to Size.Height - 1 do
begin
Source := ScanLine[i];
Target := Image.ScanLine[i];
for j := 1 to Size.Width do
begin
Target^ := Source^;
Inc(Source);
Inc(Target);
end;
end;
end;
constructor TRasterImage.Create(const Size: TInteger32Size; Components: TRasterImageComponents; AlphaMode: TAlphaMode);
begin
inherited Create();
FSize := Size;
FComponents := Components;
FAlphaMode := AlphaMode;
end;
function TRasterImage.CreateSubimage(const Bounds: TInteger32Rectangle): TRasterImage;
begin
Result := TRasterSubimage.Create(Self, Bounds);
end;
procedure TRasterImage.FlipVertically();
var
Swap: TRgbColor;
i: TInteger32;
j: TInteger32;
Top: PRgbColor;
Bottom: PRgbColor;
begin
if Components <> TRasterImageComponents.Rgba then
raise ERasterImage.Create('Operation currently only supports RGBA');
Top := ScanLine[0];
Bottom := ScanLine[Size.Height - 1];
for i := 1 to Size.Height div 2 do
begin
for j := 1 to Size.Width do
begin
Swap := Top^;
Top^ := Bottom^;
Bottom^ := Swap;
Inc(Top);
Inc(Bottom);
end;
Dec(Bottom, Size.Width * 2);
end;
end;
function TRasterImage.PremultiplyAlpha(): TRasterImage;
var
i: TInteger32;
j: TInteger32;
Source: PRgbColor;
Target: PRgbColor;
begin
if Components <> TRasterImageComponents.Rgba then
raise ERasterImage.Create('Operation currently only supports RGBA');
if AlphaMode = amNormal then
begin
Result := TPhysicalRasterImage.Create(Size, Components, amPremultiplied);
for i := 0 to Size.Height - 1 do
begin
Source := ScanLine[i];
Target := Result.ScanLine[i];
for j := 1 to Size.Width do
begin
Target.Red := (Source.Red * Source.Alpha) div $FF;
Target.Green := (Source.Green * Source.Alpha) div $FF;
Target.Blue := (Source.Blue * Source.Alpha) div $FF;
Target.Alpha := Source.Alpha;
Inc(Source);
Inc(Target);
end;
end;
end
else
raise EException.Create('Cannot premultiply alpha');
end;
{ TRasterImageRgba }
function TRasterImageRgba.GetSampleSize(): TInteger32;
begin
Result := 4;
end;
{ TRasterImageGray }
function TRasterImageGray.GetSampleSize(): TInteger32;
begin
Result := 1;
end;
{ TRasterImageComponents }
class destructor TRasterImageComponents.Destroy();
begin
Rgba.Free();
Gray.Free();
end;
class constructor TRasterImageComponents.Create();
begin
Rgba := TRasterImageRgba.Create();
Gray := TRasterImageGray.Create();
end;
end.
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