fortrangoingonforty/fgof-screen / 883069f

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Harden screen rendering

Authored by espadonne
SHA
883069f8b736cffb013b625da8fed7b9b6876247
Parents
7946628
Tree
9ebdb03

4 changed files

StatusFile+-
M README.md 4 1
M src/fgof_screen.f90 16 3
M test/test_screen_render_ansi.f90 3 2
M test/test_screen_render_edges.f90 16 0
README.mdmodified
@@ -38,6 +38,8 @@ Tracked today:
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 - explicit cursor-state ANSI output
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 - tracked example programs for full-frame and diff rendering
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 - render-edge coverage for empty screens and cursor-only diffs
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+- full-frame ANSI output with explicit row addressing
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+- render-time sanitization for non-printable control glyphs
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 - CI on macOS and Ubuntu, including direct example execution
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 - row-first, column-second grid semantics pinned down in tests
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 - focused scaffold coverage in `fpm test`
@@ -92,10 +94,11 @@ Current semantics:
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 - `diff_screen(previous, current)` compares two virtual frames and reports cell damage separately from size or cursor changes
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 - `screen_diff%damage` uses one bounding rectangle plus a `changed_cells` count for the changed frame area
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 - newly added or removed visible cells from resizes count as changed damage even when their glyphs are blank
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-- `render_screen_ansi()` emits a whole-frame ANSI repaint with clear/home semantics and final cursor restoration
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+- `render_screen_ansi()` emits a whole-frame ANSI repaint with clear/home semantics, explicit row addressing, and final cursor restoration
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 - `render_screen_diff_ansi()` emits a damage-scoped ANSI repaint and uses blank cells to erase removed content after shrinks
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 - `render_cursor_ansi()` emits the final cursor move plus visibility state for a screen buffer
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 - ANSI row rendering tracks style transitions explicitly and resets back to default style when needed
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+- ANSI renderers replace ASCII control glyphs with `?` so screen cells cannot inject raw control bytes into the output stream
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 ## Build And Test
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src/fgof_screen.f90modified
@@ -247,8 +247,8 @@ contains
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     if (allocated(buffer%cells)) then
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       do row = 1, size(buffer%cells, 1)
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+        output = output // move_cursor_ansi(row, 1)
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         output = output // render_current_row_ansi(buffer, row, 1, size(buffer%cells, 2))
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-        if (row < size(buffer%cells, 1)) output = output // new_line("a")
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       end do
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     end if
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@@ -415,7 +415,7 @@ contains
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         end if
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         current_key = cell_key
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       end if
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-      output = output // cell%glyph
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+      output = output // renderable_glyph(cell%glyph)
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     end do
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     if (len(current_key) > 0) then
@@ -449,7 +449,7 @@ contains
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         end if
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         current_key = cell_key
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       end if
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-      output = output // cell%glyph
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+      output = output // renderable_glyph(cell%glyph)
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     end do
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     if (len(current_key) > 0) then
@@ -567,4 +567,17 @@ contains
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     text = trim(scratch)
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   end function integer_text
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+  function renderable_glyph(glyph) result(output)
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+    character(len=1), intent(in) :: glyph
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+    character(len=1) :: output
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+    integer :: code
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+
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+    code = iachar(glyph)
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+    if (code < 32 .or. code == 127) then
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+      output = "?"
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+    else
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+      output = glyph
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+    end if
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+  end function renderable_glyph
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+
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 end module fgof_screen
test/test_screen_render_ansi.f90modified
@@ -28,9 +28,10 @@ program test_screen_render_ansi
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   call set_cursor(previous, 2, 1)
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   expected = esc // "?25l" // esc // "2J" // esc // "H" // &
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-             "AB" // new_line("a") // "CD" // esc // "0m" // esc // "2;1H" // esc // "?25h"
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+             esc // "1;1H" // "AB" // esc // "2;1H" // "CD" // &
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+             esc // "0m" // esc // "2;1H" // esc // "?25h"
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   rendered = render_screen_ansi(previous)
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-  if (rendered /= expected) error stop "render_screen_ansi should render a full blank-style frame deterministically"
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+  if (rendered /= expected) error stop "render_screen_ansi should use explicit row addressing for full-frame repaints"
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   style = clear_screen_style()
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   style%fg = 33
test/test_screen_render_edges.f90modified
@@ -1,6 +1,7 @@
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 program test_screen_render_edges
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   use fgof_screen, only : &
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     allocate_screen, &
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+    put_glyph, &
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     render_screen_ansi, &
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     render_screen_diff_ansi, &
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     set_cursor
@@ -35,4 +36,19 @@ program test_screen_render_edges
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   rendered = render_screen_diff_ansi(previous, current)
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   expected = esc // "?25l"
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   if (rendered /= expected) error stop "cursor-visibility-only diffs should render only the visibility change"
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+
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+  current = allocate_screen(2, 1)
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+  call put_glyph(current, 1, 1, achar(27))
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+  call put_glyph(current, 1, 2, new_line("a"))
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+  rendered = render_screen_ansi(current)
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+  expected = esc // "?25l" // esc // "2J" // esc // "H" // &
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+             esc // "1;1H" // "??" // esc // "0m" // esc // "1;1H" // esc // "?25h"
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+  if (rendered /= expected) error stop "full renders should sanitize control glyphs before emitting ANSI output"
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+
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+  previous = allocate_screen(2, 1)
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+  current = previous
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+  call put_glyph(current, 1, 2, achar(9))
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+  rendered = render_screen_diff_ansi(previous, current)
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+  expected = esc // "?25l" // esc // "1;2H" // "?" // esc // "0m" // esc // "1;1H" // esc // "?25h"
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+  if (rendered /= expected) error stop "diff renders should sanitize control glyphs before emitting ANSI output"
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 end program test_screen_render_edges