enable fb. blocking: monospace drawing

Editor.xaml.fs

@@ -119,39 +119,56 @@ type Editor() as this =
 
  fg_brush, bg_brush, sp_brush, typeface, attrs
 
+ //-------------------------------------------------------------------------
+ // = The rounding error of the rendering system: =
+ //
+ // Suppose our grid is arranged uniformly with the height of the font:
+ //
+ // Y_line = row * H_font
+ //
+ // Here, row is an integer and H_font float. We then have line Y positions
+ // as a sequence of incrementing floats: [ 0 * H_font; 1 * H_font; ... ]
+ // Suppose the whole grid is rendered in one pass, the lines will be drawn
+ // with coordinates:
+ //
+ // [ {0Hf, 1Hf}; {1Hf, 2Hf}; {2Hf, 3Hf} ... ]
+ //
+ // Clearly this is overlapping. In a pixel-based coordinate system we simply
+ // reduce the line height by one pixel. However now we are in a float co-
+ // ordinate system.. The overlapped rectangles are drawn differently -- not
+ // only that they don't overlap, they leave whitespace gaps in between!
+ // To compensate, we have to manually do the rounding to snap the pixels...
+ //-------------------------------------------------------------------------
+ // like this:
+ let rounding (pt: Point) =
+ let px = pt * grid_scale
+ Point(Math.Ceiling px.X, Math.Ceiling px.Y) / grid_scale
+
  let drawBuffer (ctx: IDrawingContextImpl) row col colend hlid (str: string list) =
  let fg, bg, sp, typeface, attrs = getDrawAttrs hlid
 
- let text = FormattedText()
- text.Text <- str |> String.Concat
- text.Typeface <- typeface
- text.TextAlignment <- TextAlignment.Left
-
- let topLeft = getPoint row col
- let bottomRight = topLeft + getPoint 1 (colend - col)
- let fontPos = topLeft 
-
- // now, make sure the background snaps to the device pixels.
- //let rounding (x: float) =
- // Math.Truncate x
-
- // mind the linespace padding.
- //let topLeft = topLeft * grid_scale
- //let topLeft = Point(rounding topLeft.X, rounding topLeft.Y - grid_linespace) / grid_scale
- //let bottomRight = bottomRight * grid_scale
- //let bottomRight = Point(rounding bottomRight.X, rounding bottomRight.Y - grid_linespace) / grid_scale
+ let topLeft = getPoint row col |> rounding
+ let bottomRight = (topLeft + getPoint 1 (colend - col)) |> rounding
  let bg_region = Rect(topLeft , bottomRight)
 
  //printfn "drawText: %d %d -> %f %f" row col fontPos.Y fontPos.X
  //trace "drawText: %d %d-%d hlid=%A" row col colend hlid
  ctx.FillRectangle(bg, bg_region)
- ctx.DrawText(fg, fontPos, text.PlatformImpl)
+
+ let text = FormattedText()
+ text.Typeface <- typeface
+ text.TextAlignment <- TextAlignment.Left
+ str |> List.iteri (fun i t ->
+ let fontPos = rounding(topLeft + getPoint 0 i)
+ text.Text <- t
+ ctx.DrawText(fg, fontPos, text.PlatformImpl)
+ )
 
  // assembles text from grid and draw onto the context.
  let drawBufferLine (ctx: IDrawingContextImpl) y x0 xN =
  let xN = min xN grid_size.cols
  let x0 = max x0 0
- let y = (min y grid_size.rows - 1 ) |> max 0
+ let y = (min y (grid_size.rows - 1) ) |> max 0
  let mutable x' = xN - 1
  let mutable hlid = grid_buffer.[y, x'].hlid
  let mutable str = []
@@ -199,6 +216,7 @@ type Editor() as this =
  this.InvalidateVisual()
 
  let setFont name size =
+ let size = max size 1.0
  let ff = ui.FindFontFace name
  font_family <- ff.Name
  font_size <- size
@@ -207,14 +225,12 @@ type Editor() as this =
  typeface_bold <- Typeface(ff, font_size, FontStyle.Normal, FontWeight.Bold)
 
  let txt = FormattedText()
- txt.Text <- "X"
+ txt.Text <- "@"
  txt.Typeface <- typeface_bold
  glyph_size <- txt.Bounds.Size
- glyph_size <- glyph_size.WithHeight(glyph_size.Height + 2.0 * grid_linespace)
- //glyph_size <- Size(Math.Truncate glyph_size.Width, Math.Truncate glyph_size.Height)
+ glyph_size <- glyph_size.WithHeight(glyph_size.Height + grid_linespace)
 
  trace "setFont" "request=%s actual=%s size=%A %A" name font_family glyph_size glyph_size
- //printfn "setFont: request=%s actual=%s size=%A %A" name font_family glyph_size glyph_size
  resizeEvent.Trigger(this)
 
  let setHighlight x =
@@ -251,12 +267,12 @@ type Editor() as this =
  grid_dirty <- { row = 0; col = 0; height = 0; width = 0}
 
  let clearBuffer () =
- grid_scale <- Math.Sqrt <| this.GetVisualRoot().RenderScaling
+ grid_scale <- this.GetVisualRoot().RenderScaling
+ trace "redraw" "RenderScaling is %f" grid_scale
   #if USE_FRAMEBUFFER
  let size = grid_scale * grid_scale * getPoint grid_size.rows grid_size.cols
  let pxsize = PixelSize(int <| Math.Ceiling size.X, int <| Math.Ceiling size.Y)
  this.DestroyFramebuffer()
- //grid_fb <- new RenderTargetBitmap(pxsize)
  grid_fb <- new RenderTargetBitmap(pxsize, Vector(96.0 * grid_scale, 96.0 * grid_scale))
  grid_dc <- grid_fb.CreateDrawingContext(null)
   #endif
@@ -280,7 +296,7 @@ type Editor() as this =
  grid_buffer.[row, col].text <- cell.text
  col <- col + 1
  let dirty = { row = row; col = line.col_start; height = 1; width = col - line.col_start } 
- trace "redraw" "putBuffer: writing to %A" dirty
+ //trace "redraw" "putBuffer: writing to %A" dirty
  markDirty dirty
 
  let setModeInfo (cs_en: bool) (info: ModeInfo[]) =
@@ -386,13 +402,11 @@ type Editor() as this =
  if rows > 0 then
  for i = top + rows to bot do
  copy i (i-rows)
- //markDirty {row = top; height = bot - top + 1 - rows; col = left; width = right - left }
- markDirty {row = top; height = bot - top + 1 - rows; col = 0; width = grid_size.cols }
+ markDirty {row = i - rows; height = 1; col = left; width = right - left }
  elif rows < 0 then
  for i = bot + rows - 1 downto top do
  copy i (i-rows)
- //markDirty {row = top - rows; height = bot - top + 1 + rows; col = left; width = right - left }
- markDirty {row = top - rows; height = bot - top + 1 + rows; col = 0; width = grid_size.cols }
+ markDirty {row = i - rows; height = 1; col = left; width = right - left }
 
  let setOption (opt: UiOption) = 
  trace "setOption" "%A" opt
@@ -510,40 +524,46 @@ type Editor() as this =
  override this.Render(ctx) =
  if (not is_ready) then this.OnReady()
  let ctx = ctx.PlatformImpl
- let bounds = this.Bounds
 
  let doRenderBuffer() =
   #if USE_FRAMEBUFFER
  if grid_fb <> null then
  let fb_region = Rect(grid_fb.Size)
- let bounds = this.Bounds
+ let screen_size = getPoint grid_size.rows grid_size.cols
+ let bounds = Rect(0.0, 0.0, screen_size.X, screen_size.Y)
  ctx.DrawImage(grid_fb.PlatformImpl :?> IRef<IBitmapImpl>, 1.0, fb_region, bounds)
- //markClean()
   #else
  for y = grid_dirty.row to grid_dirty.row_end-1 do
  drawBufferLine ctx y grid_dirty.col grid_dirty.col_end
   #endif
+ //markClean()
+
+  #if USE_FRAMEBUFFER
+ let ctx' = grid_dc
+  #else
+ let ctx' = ctx
+  #endif
 
  let doRenderCursor() =
  let mode = mode_defs.[cursor_modeidx]
  let hlid = grid_buffer.[cursor_row, cursor_col].hlid
  let hlid = Option.defaultValue hlid mode.attr_id
 
  let _, bg, _, _, _ = getDrawAttrs hlid
- let origin = getPoint cursor_row cursor_col
+ let origin = getPoint cursor_row cursor_col |> rounding
 
- let cellw p = min (double(p) / 100.0 * glyph_size.Width) 5.0
- let cellh p = min (double(p) / 100.0 * glyph_size.Height) 5.0
+ let cellw p = min (double(p) / 100.0 * glyph_size.Width) 1.0
+ let cellh p = min (double(p) / 100.0 * glyph_size.Height) 1.0
 
  match mode.cursor_shape, mode.cell_percentage with
  | Some(CursorShape.Block), _ ->
- drawBuffer ctx cursor_row cursor_col (cursor_col+1) hlid [grid_buffer.[cursor_row, cursor_col].text]
+ drawBuffer ctx' cursor_row cursor_col (cursor_col+1) hlid [grid_buffer.[cursor_row, cursor_col].text]
  | Some(CursorShape.Horizontal), Some p ->
  let region = Rect(origin + (getPoint 1 0), origin + (getPoint 1 1) - Point(0.0, cellh p))
- ctx.FillRectangle(bg, region)
+ ctx'.FillRectangle(bg, region)
  | Some(CursorShape.Vertical), Some p ->
  let region = Rect(origin, origin + (getPoint 1 0) + Point(cellw p, 0.0))
- ctx.FillRectangle(bg, region)
+ ctx'.FillRectangle(bg, region)
  | _ -> ()
 
 

MainWindow.xaml.fs

@@ -13,7 +13,7 @@ type MainWindow(datactx: FVimViewModel) as this =
  this.Closing.Add datactx.OnTerminating
  this.Closed.Add datactx.OnTerminated
  //this.Renderer.DrawDirtyRects <- true
- //this.Renderer.DrawFps <- true
+ this.Renderer.DrawFps <- true
 
  AvaloniaXamlLoader.Load this
  Avalonia.DevToolsExtensions.AttachDevTools(this);

fvim.fsproj

@@ -4,7 +4,7 @@
  <OutputType>WinExe</OutputType>
  <TargetFramework>netcoreapp2.1</TargetFramework>
  <AssemblyName>FVim</AssemblyName>
- <!--<DefineConstants>USE_FRAMEBUFFER</DefineConstants>-->
+ <DefineConstants>USE_FRAMEBUFFER</DefineConstants>
  </PropertyGroup>
 
  <ItemGroup>

log.fs

@@ -5,6 +5,7 @@ open System.Diagnostics
 let trace cat fmt =
   #if DEBUG
  //Printf.kprintf (fun s -> printfn "%s: %s" cat s) fmt
+ //Printf.kprintf (fun s -> Trace.TraceInformation(sprintf "%s: %s" cat s)) fmt
  Printf.kprintf (fun s -> Trace.WriteLine(s, cat)) fmt
   #else
  Printf.kprintf (fun s -> ()) fmt