Смысл - картинка увеличивается в нецелое количество раз, а пиксели сглаживаются только по границе. Например, если увеличение в 3,5 раз, то будет пиксель размером 3,5x3,5 (3px залито сплошным цветом, а 0,5 попадает на 4-й пиксель, и он, соответственно, сглажен цветом 3 и 4 пикселя).
Если сложно представить, то сделайте в фотошопе сначала scale до 3500% методом nearest neighbour, а затем уменьшите до 10% методом bilinear) - это будет выглядеть как scale на 350% моим методом.
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procedure ExplodeColor(const color1:tcolor;var r,g,b:Byte);
var col:longword;
begin
col:=ColorToRGB(color1);
r:=Byte(col);
g:=Byte(col shr 8);
b:=Byte(col shr 16);
end;
function AddColor(const color1,color2:tcolor):tcolor;
var r1,g1,b1:byte;
r2,g2,b2:byte;
rr,gg,bb:byte;
begin
ExplodeColor(color1,r1,g1,b1);
ExplodeColor(color2,r2,g2,b2);
if r1+r2<=255 then rr:=r1+r2 else rr:=255;
if g1+g2<=255 then gg:=g1+g2 else gg:=255;
if b1+b2<=255 then bb:=b1+b2 else bb:=255;
Result:=RGB(rr,gg,bb);
end;
procedure TForm1.Button1Click(Sender: TObject);
var x,y:integer;
scale:double;
xx,yy:integer;
src_rr,src_gg,src_bb:byte;
dst_rr,dst_gg,dst_bb:byte;
add_percent:double;
tmp_val:integer;
pixel_left:double;
pixel_top:double;
pixel_right:double;
pixel_bottom:double;
pixel_left_plus:integer;
pixel_top_plus:integer;
pixel_right_plus:integer;
pixel_bottom_plus:integer;
pixel_mult_left,pixel_mult_top:double;
pixel_mult_right,pixel_mult_bottom:double;
begin
scale:=3.5;
image1.Picture.LoadFromFile('Untitled-3.bmp');
Image2.Canvas.Create;
Image2.Picture.Graphic.Width:=round(image1.picture.width*scale);
Image2.Picture.Graphic.Height:=round(image1.picture.Height*scale);
image2.Canvas.Brush.Color:=clBlack;
image2.Canvas.FillRect(rect(0,0,image2.Picture.Graphic.Width,image2.Picture.Graphic.Height));
image2.Canvas.Brush.Color:=clWhite;
for y:=0 to Image1.Picture.Height-1 do
begin
for x:=0 to Image1.Picture.Width-1 do
begin
pixel_left:=x*scale;
pixel_top:=y*scale;
pixel_right:=(x+1)*scale;
pixel_bottom:=(y+1)*scale;
if frac(pixel_left)<1e-10 then begin pixel_left_plus:=0; pixel_mult_left:=1; end else begin pixel_left_plus:=0; pixel_mult_left:=1-frac(pixel_left); end;
if frac(pixel_top)<1e-10 then begin pixel_top_plus:=0; pixel_mult_top:=1; end else begin pixel_top_plus:=0; pixel_mult_top:=1-frac(pixel_top); end;
if frac(pixel_right)<1e-10 then begin pixel_right_plus:=-1; pixel_mult_right:=1; end else begin pixel_right_plus:=0; pixel_mult_right:=frac(pixel_right); end;
if frac(pixel_bottom)<1e-10 then begin pixel_bottom_plus:=-1; pixel_mult_bottom:=1; end else begin pixel_bottom_plus:=0; pixel_mult_bottom:=frac(pixel_bottom); end;
for xx:=trunc(pixel_left)+pixel_left_plus to trunc(pixel_right)+pixel_right_plus do
begin
for yy:=trunc(pixel_top)+pixel_top_plus to trunc(pixel_bottom)+pixel_bottom_plus do
begin
ExplodeColor(Image1.Canvas.Pixels[x,y],src_rr,src_gg,src_bb);
ExplodeColor(Image2.Canvas.Pixels[xx,yy],dst_rr,dst_gg,dst_bb);
add_percent:=1;
if (xx=trunc(pixel_left)+pixel_left_plus) and (yy=trunc(pixel_top)+pixel_top_plus) then add_percent:=((pixel_mult_left+pixel_mult_top)/2)/2;
if (xx=trunc(pixel_left)+pixel_left_plus) and (yy>trunc(pixel_top)+pixel_top_plus) and (yy<trunc(pixel_bottom)+pixel_bottom_plus) then add_percent:=pixel_mult_left;
if (xx=trunc(pixel_left)+pixel_left_plus) and (yy=trunc(pixel_bottom)+pixel_bottom_plus) then add_percent:=((pixel_mult_left+pixel_mult_bottom)/2)/2;
if (xx=trunc(pixel_right)+pixel_right_plus) and (yy=trunc(pixel_top)+pixel_top_plus) then add_percent:=((pixel_mult_right+pixel_mult_top)/2)/2;
if (xx=trunc(pixel_right)+pixel_right_plus) and (yy>trunc(pixel_top)+pixel_top_plus) and (yy<trunc(pixel_bottom)+pixel_bottom_plus) then add_percent:=pixel_mult_right;
if (xx=trunc(pixel_right)+pixel_right_plus) and (yy=trunc(pixel_bottom)+pixel_bottom_plus) then add_percent:=((pixel_mult_right+pixel_mult_bottom)/2)/2;
if (yy=trunc(pixel_top)+pixel_top_plus) and (xx>trunc(pixel_left)+pixel_left_plus) and (xx<trunc(pixel_right)+pixel_right_plus) then add_percent:=pixel_mult_top;
if (yy=trunc(pixel_bottom)+pixel_bottom_plus) and (xx>trunc(pixel_left)+pixel_left_plus) and (xx<trunc(pixel_right)+pixel_right_plus) then add_percent:=pixel_mult_bottom;
tmp_val:=Round(dst_rr+src_rr*add_percent);
if tmp_val<=255 then dst_rr:=tmp_val else dst_rr:=255;
tmp_val:=Round(dst_gg+src_gg*add_percent);
if tmp_val<=255 then dst_gg:=tmp_val else dst_gg:=255;
tmp_val:=Round(dst_bb+src_bb*add_percent);
if tmp_val<=255 then dst_bb:=tmp_val else dst_bb:=255;
Image2.Canvas.Pixels[xx,yy]:=rgb(dst_rr,dst_gg,dst_bb);
end;
end;
end;
end;
end;
Этот мой код делает картинку с артефактами, а надо без артефактов.
