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{
fpGUI - Free Pascal GUI Toolkit
Copyright (C) 2006 - 2013 See the file AUTHORS.txt, included in this
distribution, for details of the copyright.
See the file COPYING.modifiedLGPL, included in this distribution,
for details about redistributing fpGUI.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Description:
PNG image loading using the Free Pascal library: fcl-image
}
unit fpg_imgfmt_png;
{$mode objfpc}{$H+}
interface
uses
SysUtils,
Classes,
fpg_base,
fpg_main,
FPImage,
FPReadPNG;
function LoadImage_PNG(const AFileName: TfpgString): TfpgImage; overload;
function LoadImage_PNG(AStream: TStream): TfpgImage; overload;
function LoadImage_PNG(const AImageData: Pointer; const AImageDataSize: LongWord): TfpgImage; overload;
function LoadImage_PNG(AInstance: THandle; const AResName: String; AResType: PChar): TfpgImage; overload;
function LoadImage_PNGcrop(const AMaxWidth, AMaxHeight: integer; const AFileName: TfpgString): TfpgImage;
implementation
uses
fpg_utils;
function FPImageToFPG(ASource: TFPCustomImage): TfpgImage;
var
i, j: integer;
colorA: TFPColor; // struct Red, Green, Blue, Alpha: word
colorB: TfpgColor; // ONE long 32-bit-word
xlocal, ylocal: integer;
begin
Result := nil;
if ASource=nil then Exit;
xlocal := ASource.Width;
ylocal := ASource.Height;
Result := TfpgImage.Create;
Result.AllocateImage(32, xlocal, ylocal); // 32=colordepth
for i := 0 to ylocal - 1 do
for j := 0 to xlocal - 1 do
begin
colorA := ASource.Colors[j, i];
colorB := (colorA.Blue shr 8) or (colorA.Green and $FF00) or ((colorA.Red and $FF) shl 16) or ((colorA.Alpha and $FF) shl 24);
Result.Colors[j, i] := colorB;
end;
Result.UpdateImage;
end;
function LoadImage_PNG(const AFileName: TfpgString): TfpgImage;
var
imga: TFPCustomImage;
PNGReader: TFPReaderPNG;
begin
Result := nil;
if not fpgFileExists(AFileName) then
Exit; //==>
imga := TFPMemoryImage.Create(0, 0);
try
PNGReader := TFPReaderPNG.Create;
try
imga.LoadFromFile(AFileName, PNGReader); // auto size image
finally
PNGReader.Free;
end;
except
imga := nil;
end;
if imga <> nil then
begin
Result := FPImageToFPG(imga);
imga.Free;
end;
end;
function LoadImage_PNG(AStream: TStream): TfpgImage;
var
imga: TFPMemoryImage;
reader: TFPReaderPNG;
begin
Result := nil;
if AStream = nil then
Exit;
imga := TFPMemoryImage.Create(0, 0);
try
try
AStream.Position := 0;
reader := TFPReaderPNG.Create;
imga.LoadFromStream(AStream, reader); // auto size image
Result := FPImageToFPG(imga);
except
on e: Exception do
begin
Result := nil;
raise; // so we can report PNG errors (eg: missing resource name)
end;
end;
finally
reader.Free;
imga.Free;
end;
end;
function LoadImage_PNG(const AImageData: Pointer; const AImageDataSize: LongWord): TfpgImage;
var
s: TMemoryStream;
begin
s := TMemoryStream.Create;
try
s.Write(AImageData^, AImageDataSize);
Result := LoadImage_PNG(s);
finally
s.Free;
end;
end;
function LoadImage_PNG(AInstance: THandle; const AResName: String; AResType: PChar): TfpgImage;
var
res: TResourceStream;
begin
try
res := TResourceStream.Create(AInstance, AResName, AResType);
Result := LoadImage_PNG(res);
finally
if res <> nil then
res.Free;
end;
end;
function LoadImage_PNGcrop(const AMaxWidth, AMaxHeight: integer; const AFileName: TfpgString): TfpgImage;
var
i, j: integer;
colorA: TFPColor; // struct Red, Green, Blue, Alpha: word
colorB: TfpgColor; // ONE long 32-bit-word
imga: TFPCustomImage;
imgb: TfpgImage;
xlocal, ylocal: integer;
begin
Result := nil;
if not fpgFileExists(AFileName) then
Exit; //==>
// Maximum image size of AMaxWidth by AMaxHeight.
// Actual image imga.Width (AMaxWidth) and imga.Height (AMaxHeight).
// Calculated to fit the image within required size: xlocal, ylocal
imga := TFPMemoryImage.Create(0, 0);
try
imga.LoadFromFile(AFileName, TFPReaderPNG.Create); // auto size image
except
imga := nil;
imgb := nil;
end;
if imga <> nil then
begin
if imga.Width > AMaxWidth then
xlocal := AMaxWidth
else
xlocal := imga.Width;
if imga.Height > AMaxHeight then
ylocal := AMaxHeight
else
ylocal := imga.Height;
imgb := TfpgImage.Create;
imgb.AllocateImage(32, xlocal, ylocal); // 32=colordepth
for i := 0 to ylocal - 1 do
for j := 0 to xlocal - 1 do
begin
colorA := imga.Colors[j, i];
colorB := (colorA.Blue shr 8) or (colorA.Green and $FF00) or ((colorA.Red and $FF00) shl 8);
imgb.Colors[j, i] := colorB;
end;
imgb.UpdateImage;
end;
imga.Free;
Result := imgb;
end;
end.
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