使用ImageSharp放置旋转图像

Question

我试图旋转(围绕它的中心)，并将一个图像放在另一个图像的上方。

旋转后，我所期望的XY坐标是错误的。

请举例说明如何做到这一点。

当前绘制调试帧而不是图像。

我的坐标系是基于位置的中心位置，但是我可以切换到XY坐标的左上角位置

private static void DrawDebugFrames(List<LogoPlacementContentDto> placements, Image<Rgba32> mutatedImage)
{
    foreach (var placement in placements)
    {
        var width = placement.Width;
        var height = placement.Height;

        using (var logo = new Image<Rgba32>(Configuration.Default, width, height))
        {
            var centerX = placement.X; // center of imagePlacement
            var centerY = placement.Y; // center of imagePlacement

            var affineBuilder = new AffineTransformBuilder();
            affineBuilder.PrependTranslation(new Vector2(centerX, centerY));
            affineBuilder.PrependRotationDegrees(placement.Rotation);

            logo.Mutate(
                x => x
                    .BackgroundColor(Rgba32.Beige).DrawPolygon(
                        Rgba32.HotPink,
                        4,
                        new Vector2(0, 0),
                        new Vector2(width, 0),
                        new Vector2(width, height),
                        new Vector2(0, height)
                    )
                    .Transform(affineBuilder)
            );

            mutatedImage.Mutate(
                x => x
                    .DrawImage(logo, new Point(-(width / 2), -(height / 2)), GraphicsOptions.Default)
            );
        }
    }
}

(图像) 预期结果(编辑)

(图像) 结果

Answer 1

我解决了这个问题。

问题是客户端从未发送过边界框的XY坐标。相反，我尝试使用左上角的XY或XY的中间位置。

用这个固定的。我稍微调整了代码，以反映这一变化。

private static void DrawDebugFrames(List<LogoPlacementContentDto> placements, Image<Rgba32> mutatedImage)
{
    foreach (var placement in placements)
    {
        var width = placement.WidthInt;
        var height = placement.HeightInt;

        using (var logo = new Image<Rgba32>(Configuration.Default, width, height))
        {
            var positionX = placement.Position.X;
            var positionY = placement.Position.Y;

            var affineBuilder = new AffineTransformBuilder();

            affineBuilder.PrependTranslation(new Vector2(positionX, positionY));
            affineBuilder.PrependRotationDegrees(placement.Rotation);
            affineBuilder.AppendTranslation(new Vector2(-positionX, -positionY));

            logo.Mutate(
                x => x
                    .BackgroundColor(Rgba32.Beige).DrawPolygon(
                        Rgba32.HotPink,
                        4,
                    new Vector2(0, 0),
                    new Vector2(width, 0),
                    new Vector2(width, height),
                    new Vector2(0, height)
                    )
                    .Transform(affineBuilder)
            );

            mutatedImage.Mutate(
                x => x
                    .DrawImage(logo, new Point(placement.Position.XInt, placement.Position.YInt), GraphicsOptions.Default)
            );
        }
    }
}