Question

FMX.Types.TBitmap类在FMX（FireMonkey）中具有ScanLine属性，但似乎此属性已被删除，并且在FMX2（FireMonkey FM2）中缺失。

有没有解决方法？我们如何直接在FMX2中访问TBitmap内容？

Answer 1

对于直接访问，您应该使用Map方法。该文档包含许多示例，例如FMX.AlphaColorToScanline：

function TForm1.TestAlphaColorToScanline(ABitmap: TBitmap;
  start, count: integer): TBitmap;
var
  bitdata1, bitdata2: TBitmapData;
begin
  Result := TBitmap.Create(Round(ABitmap.Width), Round(count));
  if (ABitmap.Map(TMapAccess.maRead, bitdata1) and
    Result.Map(TMapAccess.maWrite, bitdata2)) then
  begin
    try
      AlphaColorToScanline(@PAlphaColorArray(bitdata1.Data)
        [start * (bitdata1.Pitch div GetPixelFormatBytes(ABitmap.PixelFormat))],
        bitdata2.Data, Round(Result.Height * Result.Width),
        ABitmap.PixelFormat);
    finally
      ABitmap.Unmap(bitdata1);
      Result.Unmap(bitdata2);
    end;
  end;
end;

Answer 2

以下是C ++ Builder的一个示例（当前的文档完全缺失）：

int X, Y;
TBitmapData bm;

// get bitmap data access !
if ( Image1->Bitmap->Map(TMapAccess::maReadWrite, bm) )
{
    unsigned int* data = (unsigned int*)bm.Data;

    // i.e. clear data with alpha color
    memset(data, 0,
    Image1->Width * Image1->Height * sizeof(unsigned int));

    // test direct pixel access here
    for (X = 20; X <= 200; X++)
    {
        for (Y = 10; Y <= 100; Y++)
        {
            //MyBitmap->Pixels[X][Y] = claLime;  // does not work anymore !
            bm.SetPixel(X, Y, claLime);
        }
    }

    // now write back the result !
    Image1->Bitmap->Unmap(bm);
}
else
{
    MessageDlg("Could not map the image data for direct access.",
    TMsgDlgType::mtWarning, TMsgDlgButtons() << TMsgDlgBtn::mbOK, 0);
}

如何直接在FMX2中访问TBitmap像素（TBitmap.ScanLine替换）？

2 个答案: