在将Delphi代码转换为C时，我发现有些复杂。
以下是Delphi的完整代码：
unit resizeunit;
{ resize bm1 to fit in bm2
bm1,bm2 bitmaps must be created and width,height set }
interface
uses windows,graphics;
procedure BMresize;
var bm1,bm2 : Tbitmap;
implementation
type PDW = ^dword;
procedure BMresize;
//copy bm1 to bm2
var ps0,pd0,psStep,pdStep : dword; //scanline[0], row steps
sx1,sy1,sx2,sy2 : single; //source field positions
x,y,i,j,destwidth,destheight : word; //source,dest field pixels
destR,destG,destB : single; //destination colors
sR,sG,sB : byte; //source colors
fx,fy,fix,fiy,dyf : single; //factors
fxstep,fystep, dx,dy : single;
color : dword;
pdy,pdx,psi,psj : dword;
AP : single;
istart,iend,jstart,jend : word;
devX1,devX2,devY1,devY2 : single;
begin
ps0 := DWORD(bm1.scanline[0]);
psstep := ps0 - DWORD(bm1.scanline[1]);
pd0 := DWORD(bm2.scanline[0]);
pdstep := pd0 - DWORD(bm2.scanline[1]);
destwidth := bm2.Width-1;
destheight := bm2.Height-1;
fx := bm1.width/ bm2.width;
fy := bm1.height/bm2.height;
fix := 1/fx;
fiy := 1/fy;
fxstep := 0.9999 * fx;
fystep := 0.9999 * fy;
pdy := pd0;
for y := 0 to destheight do //vertical destination pixels
begin
sy1 := fy * y;
sy2 := sy1 + fystep;
jstart := trunc(sy1);
jend := trunc(sy2);
devY1 := 1-sy1+jstart;
devY2 := jend+1-sy2;
pdx := pdy;
for x := 0 to destwidth do //horizontal destination pixels
begin
sx1 := fx * x; //x related values are repeated
sx2 := sx1 + fxstep; //for each y and may be placed in
istart := trunc(sx1); //lookup table
iend := trunc(sx2); //...
devX1 := 1-sx1+istart; //...
devX2 := iend+1-sx2; //...
destR := 0; destG := 0; destB := 0; //clear destination colors
psj := ps0-jstart*psStep;
dy := devY1;
for j := jstart to jend do //vertical source pixels
begin
if j = jend then dy := dy - devY2;
dyf := dy*fiy;
psi := psj + (istart shl 2);
dx := devX1;
for i := istart to iend do //horizontal source pixels
begin
if i = iend then dx := dx - devX2;
AP := dx*dyf*fix;
color := PDW(psi)^;
sB := color;
destB := destB + sB*AP;
sG := color shr 8;
destG := destG + sG*AP;
sR := color shr 16;
destR := destR + sR*AP;
inc(psi,4);
dx := 1;
end;//for i
dec(psj,psStep);
dy := 1;
end;//for j
sB := round(destB);
color := sB or (sG shl 8) or (sR shl 16);
PDW(pdx)^ := color;
inc(pdx,4);
end;//for x
dec(pdy,pdstep);
end;//for y
end;
end.
我正试图理解
关于IT技术方面的相关内容。type PDW = ^dword; ,inc(psi,4); and dec(psj,psStep);
意思。
添加
我想知道color = PDW(psi) ^;的含义； 如果我想应用一些数组变量，那我该怎么做？
这来自delphi代码。我正在尝试转换成C语言。 我以前从未接触过delphi代码。
能否请您帮我理解它们的含义并将其转换为C语言？
PDW = ^dword;是将类型PDW声明为指向DWORD的指针。inc(psi,4);是将变量psi的值增加 4。dec(psj,psStep);是将变量psj的值减去变量psStep的值。 - Victoriatypedef DWORD *PDW;作为示例呢？ - Victoria