Where to place the coordinates of text in a C# graphic bitmap

Question

I wrote a C# Render method that renders a heatmap onto a Grasshopper canvas. Grasshopper is a Rhino plugin that allows for a simple GUI programming interface.

protected override void Render(Grasshopper.GUI.Canvas.GH_Canvas canvas, Graphics graphics, Grasshopper.GUI.Canvas.GH_CanvasChannel channel) {

            base.Render(canvas, graphics, channel);

            if (channel == Grasshopper.GUI.Canvas.GH_CanvasChannel.Wires) {
                var comp = Owner as KT_HeatmapComponent;
                if (comp == null)
                    return;

                List<HeatMap> maps = comp.CachedHeatmaps;
                if (maps == null)
                    return;

                if (maps.Count == 0)
                    return;

                int x = Convert.ToInt32(Bounds.X + Bounds.Width / 2);
                int y = Convert.ToInt32(Bounds.Bottom + 10);

                for (int i = 0; i < maps.Count; i++) {
                    Bitmap image = maps[i].Image;
                    if (image == null)
                        continue;

                    Rectangle mapBounds = new Rectangle(x, y, maps[i].Width, maps[i].Height);
                    //Rectangle mapBounds = new Rectangle(x, y, maps[i].Width * 10, maps[i].Height * 10);
                    mapBounds.X -= mapBounds.Width / 2;

                    Rectangle edgeBounds = mapBounds;
                    edgeBounds.Inflate(4, 4);

                    GH_Capsule capsule = GH_Capsule.CreateCapsule(edgeBounds, GH_Palette.Normal);
                    capsule.Render(graphics, Selected, false, false);
                    capsule.Dispose();

                    graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
                    graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.Half;
                    graphics.DrawImage(image, mapBounds);
                    graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                    graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.Default;
                    graphics.DrawRectangle(Pens.Black, mapBounds);

                    y = edgeBounds.Bottom - (mapBounds.Height) - 4;
                }
            }
        }

Currently, this render methods draws an image like this onto the canvas:

With that said, I would like to put some title text on top, and put in labels for the X and Y axis, like a standard heat map graph. However, my understanding of the graphics component is too limited, and I would like to request the assistance of you guys.

I did some research, and it seems the drawText() method could do what I want: c# write text on bitmap

But I am unsure where to specify the coordinates while at the same time leaving some space on the top of the displayed graph to put the title text.

Answer 1

The coordinate system that GDI+ uses starts from the topleft corner which is (0,0) The bottom right corner (fullimagewidth,fullimageheight)

so if you need to draw on the topleft corner of the image use

//Position
PointF drawPoint = new PointF(0F, 0F);
// Draw string to screen.
e.Graphics.DrawString("hey", drawFont, drawBrush, drawPoint);