Try to fix marker size

ReferenceTests/src/tests/primitives.jl

@@ -248,6 +248,17 @@ end
     for (i, marker) in enumerate(markers)
         scatter!(Point2f.(1:5, i), marker = marker, markersize = range(10, 30, length = 5), color = :black)
         scatter!(Point2f.(1:5, i), markersize = 4, color = :white)
+
+        # # Debug - show bbox outline
+        # if !(marker isa Char)
+        #     scene = Makie.get_scene(ax)
+        #     bb = Makie.bbox(Makie.DEFAULT_MARKER_MAP[marker])
+        #     w, h = widths(bb)
+        #     ox, oy = origin(bb)
+        #     xy = map(pv -> Makie.project(pv, Vec2f(widths(pixelarea(scene)[])), Point2f(5, i)), scene.camera.projectionview)
+        #     bb = map(xy -> Rect2f(xy .+ 30 * Vec2f(ox, oy), 30 * Vec2f(w, h)), xy)
+        #     lines!(bb, linewidth = 1, color = :orange, space = :pixel, linestyle = :dash)
+        # end
     end
 
     f

src/bezier.jl

@@ -502,16 +502,24 @@ function render_path(path, bitmap_size_px = 256)
     # freetype has no ClosePath and EllipticalArc, so those need to be replaced
     path_replaced = replace_nonfreetype_commands(path)
 
-    aspect = widths(bbox(path)) / maximum(widths(bbox(path)))
-    path_unit_rect = fit_to_bbox(path_replaced, Rect2f(Point2f(0), aspect))
+    # Minimal size that becomes integer when mutliplying by 64 (target size for 
+    # atlas). This adds padding to avoid blurring/scaling factors from rounding
+    # during sdf generation
+    path_size = widths(bbox(path)) / maximum(widths(bbox(path)))
+    w = ceil(Int, 64 * path_size[1])
+    h = ceil(Int, 64 * path_size[2])
+    path_size = Vec2f(w, h) / 64f0
+
+    path_unit_rect = fit_to_bbox(path_replaced, Rect2f(Point2f(0), path_size))
 
     path_transformed = Makie.scale(path_unit_rect, scale_factor)
 
     outline_ref = make_outline(path_transformed)
 
-    # Adjust bitmap size to match path aspect
-    w = ceil(Int, bitmap_size_px * aspect[1])
-    h = ceil(Int, bitmap_size_px * aspect[2])
+    # Adjust bitmap size to match path size
+    w = ceil(Int, bitmap_size_px * path_size[1])
+    h = ceil(Int, bitmap_size_px * path_size[2])
+
     pitch = w * 1 # 8 bit gray
     pixelbuffer = zeros(UInt8, h * pitch)
     bitmap_ref = Ref{FT_Bitmap}()

src/utilities/texture_atlas.jl

@@ -70,7 +70,7 @@ function Base.show(io::IO, atlas::TextureAtlas)
     println(io, "  font_render_callback: ", length(atlas.font_render_callback))
 end
 
-const SERIALIZATION_FORMAT_VERSION = "v2"
+const SERIALIZATION_FORMAT_VERSION = "v3"
 
 # basically a singleton for the textureatlas
 function get_cache_path(resolution::Int, pix_per_glyph::Int)
@@ -481,12 +481,15 @@ function bezierpath_pad_scale_factor(atlas::TextureAtlas, bp)
     full_pixel_size_in_atlas = uv_width * Vec2f(size(atlas))
     # left + right pad - cutoff from pixel centering
     full_pad = 2f0 * atlas.glyph_padding - 1
-    return full_pad ./ (full_pixel_size_in_atlas .- full_pad)
+    # size without padding
+    unpadded_pixel_size = full_pixel_size_in_atlas .- full_pad
+    # See offset_bezierpath
+    return full_pixel_size_in_atlas ./ maximum(unpadded_pixel_size)
 end
 
 function marker_scale_factor(atlas::TextureAtlas, path::BezierPath)
-    # padded_width = (unpadded_target_width + unpadded_target_width * pad_per_unit)
-    return (1f0 .+ bezierpath_pad_scale_factor(atlas, path)) .* widths(Makie.bbox(path))
+    # See offset_bezierpath
+    return bezierpath_pad_scale_factor(atlas, path) * maximum(widths(bbox(path)))
 end
 
 function rescale_marker(atlas::TextureAtlas, pathmarker::BezierPath, font, markersize)
@@ -510,9 +513,28 @@ function rescale_marker(atlas::TextureAtlas, char::Char, font, markersize)
 end
 
 function offset_bezierpath(atlas::TextureAtlas, bp::BezierPath, markersize::Vec2, markeroffset::Vec2)
+    # - wh = widths(bbox(bp)) is the untouched size of the given bezierpath
+    # - full_pixel_size_in_atlas is the size of the signed distance field in the
+    #   texture atlas. This includes glyph padding
+    # - px_size is the size of signed distance field without padding
+    # To correct scaling on glow, stroke and AA widths in GLMakie we need to
+    # keep the aspect ratio of the aspect ratio (somewhat) correct when
+    # generating the sdf. This results in direct proportionality only for the
+    # longer dimension of wh and px_size. The shorter side becomes inaccurate
+    # due to integer rounding issues.
+    # 1. To calculate the width we can use the ratio of the proportional sides
+    #   scale = maximum(wh) / maximum(px_size)
+    # to scale the padded_size we need to display
+    #   scale * full_pixel_size_in_atlas
+    # (Part of this is moved to bezierpath_pad_scale_factor)
+    # 2. To calculate the offset we can simple move to the center of the bezier
+    #    path and consider that the center of the final marker. (From the center
+    #    scaling should be equal in ±x and ±y direction respectively.)
+
     bb = bbox(bp)
-    pad_offset = origin(bb) .- 0.5f0 .* bezierpath_pad_scale_factor(atlas, bp) .* widths(bb)
-    return markersize .* pad_offset
+    scaled_size = bezierpath_pad_scale_factor(atlas, bp) * maximum(widths(bb))
+    return markersize * (origin(bb) .+ 0.5f0 * widths(bb) .- 0.5f0 .* scaled_size)
+
 end
 
 function offset_bezierpath(atlas::TextureAtlas, bp, scale, offset)