Rotate labels on tiles generated by Maperitive

Question

I'm using custom generated tiles on web map (displayed using openlayers). Tiles are generated by maperetive and it's great. However my map is rotated -3/4Pi (openlayers has this feature) and many labels are rendered upside down. I belive maperitive has no feature to render labels relative to arbitrary angle. May be there are other options to fix this?

Answer 1

Maybe you can generate bitmap using export-bitmap command in maperetive. Then you rotate the whole. Hope this help!

Answer 2

I was able to solve the problem (to some degree) altering dll's of Maperitive using ILSpy & Reflexil.

If someone is interested, rendering of labels is done by GdiPainter.DrawText(string, IPointF2List, ...) method (from Karta.dll). It uses Brejc.Geometry.Algorithms.Polylines.Analysis.PolylineWalker class (from Brejc.Geospatial.dll), which controls placement of individual characters across polyline. I altered this class to make it walk along the polyline in the opposite direction.

public class PolylineWalker : IPolylineWalker
{
    private readonly PolylineAnalysis polylineAnalysis;

    private float currentOffset;

    private int currentSegment;

    private float currentOffsetWithinSegment;

    private float polylineLength;

    public float CurrentAngle
    {
        get
        {
            return this.polylineAnalysis.SegmentAngles[this.currentSegment] + 180f;
        }
    }

    public float CurrentOffsetWithinSegment
    {
        get
        {
            return this.currentOffsetWithinSegment;
        }
    }

    public Brejc.Geometry.PointF2 CurrentPoint
    {
        get
        {
            float num;
            float num2;
            this.polylineAnalysis.Points.GetPoint(this.currentSegment, out num, out num2);
            float num3;
            float num4;
            this.polylineAnalysis.Points.GetPoint(this.currentSegment + 1, out num3, out num4);
            float num5 = this.currentOffsetWithinSegment / this.polylineAnalysis.SegmentLengths[this.currentSegment];
            float x = (num - num3) * num5 + num3;
            float y = (num2 - num4) * num5 + num4;
            return new Brejc.Geometry.PointF2(x, y);
        }
    }

    public float CurrentOffset
    {
        get
        {
            return this.currentOffset;
        }
    }

    public int CurrentSegment
    {
        get
        {
            return this.currentSegment;
        }
    }

    public float LengthLeftOnSegment
    {
        get
        {
            return this.polylineAnalysis.SegmentLengths[this.currentSegment] - this.currentOffsetWithinSegment;
        }
    }

    public PolylineWalker(PolylineAnalysis polylineAnalysis)
    {
        this.polylineAnalysis = polylineAnalysis;
        this.polylineLength = polylineAnalysis.PolylineLength;
    }

    public void MoveBy(float delta)
    {
        if (delta.IsZero())
        {
            return;
        }
        if (this.currentOffset + delta > this.polylineLength)
        {
            throw new System.ArgumentOutOfRangeException("delta");
        }
        if (this.currentOffset + delta == this.polylineLength)
        {
            int num = 0;
            num++;
        }
        float num2 = this.currentOffset + delta;
        this.currentOffset -= this.currentOffsetWithinSegment;
        if (delta > 0f)
        {
            while (this.currentSegment >= 0)
            {
                this.currentOffset += this.polylineAnalysis.SegmentLengths[this.currentSegment];
                if (this.currentOffset >= num2)
                {
                    this.currentOffsetWithinSegment = num2 - (this.currentOffset - this.polylineAnalysis.SegmentLengths[this.currentSegment]);
                    this.currentOffset = num2;
                    return;
                }
                this.currentSegment--;
            }
            throw new System.InvalidOperationException("Bug in the algorithm");
        }
        this.MoveTo(num2);
    }

    public void MoveTo(float offset)
    {
        if (offset < 0f)
        {
            throw new System.ArgumentOutOfRangeException("offset");
        }
        if (offset > this.polylineLength)
        {
            throw new System.ArgumentOutOfRangeException("offset");
        }
        this.currentOffset = 0f;
        this.currentSegment = this.polylineAnalysis.SegmentsCount - 1;
        while (this.currentSegment >= 0)
        {
            if (this.currentOffset + this.polylineAnalysis.SegmentLengths[this.currentSegment] >= offset)
            {
                this.currentOffsetWithinSegment = offset - this.currentOffset;
                this.currentOffset = offset;
                return;
            }
            this.currentOffset += this.polylineAnalysis.SegmentLengths[this.currentSegment];
            this.currentSegment--;
        }
        throw new System.InvalidOperationException("Bug in the algorithm");
    }
}