autosnap can be configured

README.md

@@ -86,12 +86,22 @@ FVimDrawFPS v:true
 
 " Font tweaks
 FVimFontAntialias v:true
-FVimFontDrawBounds v:true
 FVimFontAutohint v:true
 FVimFontSubpixel v:true
 FVimFontLcdRender v:true
 FVimFontHintLevel 'full'
 
+" Try to snap the fonts to the pixels, reduces blur
+" in some situations (e.g. 100% DPI).
+FVimFontAutoSnap v:true 
+
+" Font weight tuning, possible valuaes are 100..900
+FVimFontNormalWeight 400
+FVimFontBoldWeight 700
+
+" Font debugging -- draw bounds around each glyph
+FVimFontDrawBounds v:true
+
 " Detach from a remote session without killing the server
 " If this command is executed on a standalone instance,
 " the embedded process will be terminated anyway.

neovim/neovim.model.fs

@@ -354,6 +354,7 @@ let Start opts =
 
     // rpc handlers
     List.iter ignore [
+        Notify "font.autosnap"      (fun [| Bool(v) |] -> ui.autosnap <- v)
         Notify "font.antialias"     (fun [| Bool(v) |] -> ui.antialiased <- v)
         Notify "font.bounds"        (fun [| Bool(v) |] -> ui.drawBounds <- v)
         Notify "font.autohint"      (fun [| Bool(v) |] -> ui.autohint <- v)
@@ -424,6 +425,7 @@ let Start opts =
         let! _ = Async.AwaitTask(nvim.``command!`` "-complete=expression FVimDrawFPS" 1 (sprintf "call rpcnotify(%d, 'DrawFPS', <args>)" myChannel))
         let! _ = Async.AwaitTask(nvim.``command!`` "FVimDetach" 0 (sprintf "call rpcnotify(%d, 'remote.detach')" myChannel))
 
+        let! _ = Async.AwaitTask(nvim.``command!`` "-complete=expression FVimFontAutoSnap" 1 (sprintf "call rpcnotify(%d, 'font.autosnap', <args>)" myChannel))
         let! _ = Async.AwaitTask(nvim.``command!`` "-complete=expression FVimFontAntialias" 1 (sprintf "call rpcnotify(%d, 'font.antialias', <args>)" myChannel))
         let! _ = Async.AwaitTask(nvim.``command!`` "-complete=expression FVimFontDrawBounds" 1 (sprintf "call rpcnotify(%d, 'font.bounds', <args>)" myChannel))
         let! _ = Async.AwaitTask(nvim.``command!`` "-complete=expression FVimFontAutohint" 1 (sprintf "call rpcnotify(%d, 'font.autohint', <args>)" myChannel))

ui.fs

@@ -69,6 +69,7 @@ module ui =
     let mutable autohint     = false
     let mutable subpixel     = true
     let mutable lcdrender    = true
+    let mutable autosnap     = true
     let mutable hintLevel    = SKPaintHinting.NoHinting
     let mutable private normalWeight = SKFontStyleWeight.Normal
     let mutable private boldWeight   = SKFontStyleWeight.Bold
@@ -276,7 +277,7 @@ module ui =
         let mutable w = 0.0
         let mutable h = 0.0
 
-        for sizeStep = -50 to 50 do
+        let search (sizeStep: int) =
             let s' = fontSize + float(sizeStep) * 0.01
             paint.TextSize <- single s'
 
@@ -294,6 +295,9 @@ module ui =
                 h <- h'
                 s <- s'
 
+        if autosnap then [-50 .. 50] else [0] 
+        |> List.iter search
+
         s, w, h
 
     let AllocateFramebuffer w h scale =
@@ -326,7 +330,7 @@ module ui =
         //  total_padding = padding space 1 + padding space 2
         let total_padding = h - ((float fg.FontMetrics.Bottom - float fg.FontMetrics.Top) )
         let baseline      = region.Y + floor((total_padding / 2.0) - (float fg.FontMetrics.Top))
-        let snappedBaseline = ceil(baseline * scale) / scale
+        let snappedBaseline = floor(baseline * scale) / scale
         let region = region.WithY(region.Y + snappedBaseline - baseline)
         (*printfn "scale=%A pad=%A base=%A region=%A" scale total_padding baseline region*)
         let fontPos       = Point(region.X, snappedBaseline)