移动位图像素 [英] Moving bitmap pixels

问题描述

如果我想移动/移动位图的像素，我该怎么做？

procedure MovePixels(Bitmap: TBitmap; Horizontal, Vertical: Integer);
begin
  { move the Bitmap pixels to new position }
end;

示例：

通过调用 MovePixels（Image1.Picture.Bitmap，20,20） 例如将输出如下：

还可以指定/更改移动像素后剩下的画布的颜色。所以在这个例子中，灰色/棕色可以是蓝色等。

It would be useful to also specify / change the color of the canvas that is left showing after moving the pixels. So in this example that gray / brown color could be blue etc.

我注意到有 Bitmap.Canvas.Pixels 和 Bitmap.Canvas.MoveTo 属性，这是我需要做的吗？

I noticed there is Bitmap.Canvas.Pixels and Bitmap.Canvas.MoveTo properties, is this what I would need to do this?

我真的很不知道，我敢打赌它很简单..

I really don't know and I bet it is so simple..

推荐答案

你不能轻易移动像素，复制。

You can't easily move pixels, but you can make a copy.

var
  Source, Dest: TRect;
....
Source := Rect(0, 0, Bitmap.Width, Bitmap.Height);
Dest := Source;
Dest.Offset(X, Y);
Bitmap.Canvas.CopyRect(Dest, Bitmap.Canvas, Source);

剩下的是填充你所选择的颜色，我相信你可以做的很容易，几次调用 FillRect 。

What remains is to fill in the space with the colour of your choice which I am sure you can do easily enough with a couple of calls to FillRect.

但是，我认为不会尝试更简单这个就位。相反，我会创建一个新的位图。也许这样：

However, I think that it would be simpler not to attempt this in-place. Instead I would create a new bitmap. Perhaps like this:

function CreateMovedImage(Bitmap: TBitmap; X, Y: Integer; BackColor: TColor): TBitmap;
var
  Source, Dest: TRect;
begin
  Source := Rect(0, 0, Bitmap.Width, Bitmap.Height);
  Dest := Source;
  Dest.Offset(X, Y);

  Result := TBitmap.Create;
  Try
    Result.SetSize(Bitmap.Width, Bitmap.Height);

    Result.Canvas.Brush.Style := bsSolid;
    Result.Canvas.Brush.Color := BackColor;
    Result.Canvas.FillRect(Source);

    Result.Canvas.CopyRect(Dest, Bitmap.Canvas, Source);
  Except
    Result.Free;
    raise;
  End;
end;

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