diff options
| -rw-r--r-- | README.md | 4 | ||||
| -rw-r--r-- | drawing.lua | 2 | ||||
| -rw-r--r-- | main.lua | 5 | ||||
| -rw-r--r-- | text.lua | 125 | ||||
| -rw-r--r-- | undo.lua | 78 |
5 files changed, 214 insertions, 0 deletions
diff --git a/README.md b/README.md index 68999f3..871379d 100644 --- a/README.md +++ b/README.md @@ -6,6 +6,10 @@ http://akkartik.name/lines.html * No support yet for Unicode graphemes spanning multiple codepoints. +* Undo is extremely inefficient in space. While this app is extremely unlikely + to lose the current state of a file at any moment, undo history is volatile + and should be considered unstable. + * The text cursor will always stay on the screen. This can have some strange implications: diff --git a/drawing.lua b/drawing.lua index 6b5b6c2..f3433a0 100644 --- a/drawing.lua +++ b/drawing.lua @@ -206,6 +206,7 @@ function Drawing.in_drawing(drawing, x,y) end function Drawing.mouse_pressed(drawing, x,y, button) + Drawing.before = snapshot_everything() if Current_drawing_mode == 'freehand' then drawing.pending = {mode=Current_drawing_mode, points={{x=Drawing.coord(x-16), y=Drawing.coord(y-drawing.y)}}} elseif Current_drawing_mode == 'line' or Current_drawing_mode == 'manhattan' then @@ -347,6 +348,7 @@ function Drawing.mouse_released(x,y, button) end end save_to_disk(Lines, Filename) + record_undo_event({before=Drawing.before, after=snapshot_everything()}) end function Drawing.keychord_pressed(chord) diff --git a/main.lua b/main.lua index a6b0d73..9372207 100644 --- a/main.lua +++ b/main.lua @@ -65,6 +65,10 @@ Zoom = 1.5 Filename = love.filesystem.getUserDirectory()..'/lines.txt' +-- undo +History = {} +Next_history = 1 + end -- App.initialize_globals function App.initialize(arg) @@ -102,6 +106,7 @@ function App.initialize(arg) end -- App.initialize function App.filedropped(file) + App.initialize_globals() -- in particular, forget all undo history Filename = file:getFilename() file:open('r') Lines = load_from_file(file) diff --git a/text.lua b/text.lua index d86e2bc..b35de4e 100644 --- a/text.lua +++ b/text.lua @@ -3,6 +3,8 @@ Text = {} local utf8 = require 'utf8' +require 'undo' + -- return values: -- y coordinate drawn until in px -- position of start of final screen line drawn @@ -1091,6 +1093,83 @@ function test_backspace_to_start_of_line() check_nil(Selection1.line, "F - test_backspace_to_start_of_line/selection") end +function test_undo_insert_text() + io.write('\ntest_undo_insert_text') + App.screen.init{width=120, height=60} + Lines = load_array{'abc', 'def', 'xyz'} + Line_width = App.screen.width + Cursor1 = {line=2, pos=4} + Screen_top1 = {line=1, pos=1} + Screen_bottom1 = {} + Zoom = 1 + -- insert a character + App.run_after_textinput('g') + check_eq(Cursor1.line, 2, 'F - test_undo_insert_text/baseline/cursor:line') + check_eq(Cursor1.pos, 5, 'F - test_undo_insert_text/baseline/cursor:pos') + check_nil(Selection1.line, 'F - test_undo_insert_text/baseline/selection:line') + check_nil(Selection1.pos, 'F - test_undo_insert_text/baseline/selection:pos') + local screen_top_margin = 15 -- pixels + local line_height = 15 -- pixels + local y = screen_top_margin + App.screen.check(y, 'abc', 'F - test_undo_insert_text/baseline/screen:1') + y = y + line_height + App.screen.check(y, 'defg', 'F - test_undo_insert_text/baseline/screen:2') + y = y + line_height + App.screen.check(y, 'xyz', 'F - test_undo_insert_text/baseline/screen:3') + -- undo + App.run_after_keychord('M-z') + check_eq(Cursor1.line, 2, 'F - test_undo_insert_text/cursor:line') + check_eq(Cursor1.pos, 4, 'F - test_undo_insert_text/cursor:pos') + check_nil(Selection1.line, 'F - test_undo_insert_text/selection:line') + check_nil(Selection1.pos, 'F - test_undo_insert_text/selection:pos') + y = screen_top_margin + App.screen.check(y, 'abc', 'F - test_undo_insert_text/screen:1') + y = y + line_height + App.screen.check(y, 'def', 'F - test_undo_insert_text/screen:2') + y = y + line_height + App.screen.check(y, 'xyz', 'F - test_undo_insert_text/screen:3') +end + +function test_undo_delete_text() + io.write('\ntest_undo_delete_text') + App.screen.init{width=120, height=60} + Lines = load_array{'abc', 'defg', 'xyz'} + Line_width = App.screen.width + Cursor1 = {line=2, pos=5} + Screen_top1 = {line=1, pos=1} + Screen_bottom1 = {} + Zoom = 1 + -- delete a character + App.run_after_keychord('backspace') + check_eq(Cursor1.line, 2, 'F - test_undo_delete_text/baseline/cursor:line') + check_eq(Cursor1.pos, 4, 'F - test_undo_delete_text/baseline/cursor:pos') + check_nil(Selection1.line, 'F - test_undo_delete_text/baseline/selection:line') + check_nil(Selection1.pos, 'F - test_undo_delete_text/baseline/selection:pos') + local screen_top_margin = 15 -- pixels + local line_height = 15 -- pixels + local y = screen_top_margin + App.screen.check(y, 'abc', 'F - test_undo_delete_text/baseline/screen:1') + y = y + line_height + App.screen.check(y, 'def', 'F - test_undo_delete_text/baseline/screen:2') + y = y + line_height + App.screen.check(y, 'xyz', 'F - test_undo_delete_text/baseline/screen:3') + -- undo +--? -- after undo, the backspaced key is selected + App.run_after_keychord('M-z') + check_eq(Cursor1.line, 2, 'F - test_undo_delete_text/cursor:line') + check_eq(Cursor1.pos, 5, 'F - test_undo_delete_text/cursor:pos') + check_nil(Selection1.line, 'F - test_undo_delete_text/selection:line') + check_nil(Selection1.pos, 'F - test_undo_delete_text/selection:pos') +--? check_eq(Selection1.line, 2, 'F - test_undo_delete_text/selection:line') +--? check_eq(Selection1.pos, 4, 'F - test_undo_delete_text/selection:pos') + y = screen_top_margin + App.screen.check(y, 'abc', 'F - test_undo_delete_text/screen:1') + y = y + line_height + App.screen.check(y, 'defg', 'F - test_undo_delete_text/screen:2') + y = y + line_height + App.screen.check(y, 'xyz', 'F - test_undo_delete_text/screen:3') +end + function Text.compute_fragments(line, line_width) --? print('compute_fragments', line_width) line.fragments = {} @@ -1142,6 +1221,8 @@ end function Text.insert_at_cursor(t) if Selection1.line then Text.delete_selection() end + -- Collect what you did in an event that can be undone. + local before = snapshot_everything() local byte_offset if Cursor1.pos > 1 then byte_offset = utf8.offset(Lines[Cursor1.line].data, Cursor1.pos) @@ -1152,6 +1233,8 @@ function Text.insert_at_cursor(t) Lines[Cursor1.line].fragments = nil Lines[Cursor1.line].screen_line_starting_pos = nil Cursor1.pos = Cursor1.pos+1 + -- finalize undo event + record_undo_event({before=before, after=snapshot_everything()}) end -- Don't handle any keys here that would trigger love.textinput above. @@ -1159,6 +1242,7 @@ function Text.keychord_pressed(chord) --? print(chord) --== shortcuts that mutate text if chord == 'return' then + local before = snapshot_everything() local byte_offset = utf8.offset(Lines[Cursor1.line].data, Cursor1.pos) table.insert(Lines, Cursor1.line+1, {mode='text', data=string.sub(Lines[Cursor1.line].data, byte_offset)}) local scroll_down = (Cursor_y + math.floor(15*Zoom)) > App.screen.height @@ -1171,12 +1255,18 @@ function Text.keychord_pressed(chord) Screen_top1.line = Cursor1.line Text.scroll_up_while_cursor_on_screen() end + record_undo_event({before=before, after=snapshot_everything()}) elseif chord == 'tab' then + local before = snapshot_everything() Text.insert_at_cursor('\t') save_to_disk(Lines, Filename) + record_undo_event({before=before, after=snapshot_everything()}) elseif chord == 'backspace' then + local before = snapshot_everything() if Selection1.line then Text.delete_selection() + save_to_disk(Lines, Filename) + record_undo_event({before=before, after=snapshot_everything()}) return end if Cursor1.pos > 1 then @@ -1210,9 +1300,13 @@ function Text.keychord_pressed(chord) end assert(Text.le1(Screen_top1, Cursor1)) save_to_disk(Lines, Filename) + record_undo_event({before=before, after=snapshot_everything()}) elseif chord == 'delete' then + local before = snapshot_everything() if Selection1.line then Text.delete_selection() + save_to_disk(Lines, Filename) + record_undo_event({before=before, after=snapshot_everything()}) return end if Cursor1.pos <= utf8.len(Lines[Cursor1.line].data) then @@ -1238,6 +1332,37 @@ function Text.keychord_pressed(chord) end end save_to_disk(Lines, Filename) + record_undo_event({before=before, after=snapshot_everything()}) + -- undo/redo really belongs in main.lua, but it's here so I can test the + -- text-specific portions of it + elseif chord == 'M-z' then + local event = undo_event() + if event then + local src = event.before + Screen_top1 = deepcopy(src.screen_top) + Cursor1 = deepcopy(src.cursor) + Selection1 = deepcopy(src.selection) + if src.lines then + Lines = deepcopy(src.lines) + end + end + elseif chord == 'M-y' then + local event = redo_event() + if event then + local src = event.after + Screen_top1 = deepcopy(src.screen_top) + Cursor1 = deepcopy(src.cursor) + Selection1 = deepcopy(src.selection) + if src.lines then + Lines = deepcopy(src.lines) +--? for _,line in ipairs(Lines) do +--? if line.mode == 'drawing' then +--? print('restoring', line.points, 'with', #line.points, 'points') +--? print('restoring', line.shapes, 'with', #line.shapes, 'shapes') +--? end +--? end + end + end -- paste elseif chord == 'M-c' then local s = Text.selection() diff --git a/undo.lua b/undo.lua new file mode 100644 index 0000000..abf5f33 --- /dev/null +++ b/undo.lua @@ -0,0 +1,78 @@ +-- undo/redo by managing the sequence of events in the current session +-- based on https://github.com/akkartik/mu1/blob/master/edit/012-editor-undo.mu + +-- Incredibly inefficient; we make a copy of lines on every single keystroke. +-- The hope here is that we're either editing small files or just reading large files. +-- TODO: highlight stuff inserted by any undo/redo operation +-- TODO: coalesce multiple similar operations + +function record_undo_event(data) + History[Next_history] = data + Next_history = Next_history+1 + for i=Next_history,#History do + History[i] = nil + end +end + +function undo_event() + if Next_history > 1 then +--? print('moving to history', Next_history-1) + Next_history = Next_history-1 + local result = History[Next_history] + return result + end +end + +function redo_event() + if Next_history <= #History then +--? print('restoring history', Next_history+1) + local result = History[Next_history] + Next_history = Next_history+1 + return result + end +end + +-- Make copies of objects; the rest of the app may mutate them in place, but undo requires immutable histories. +function snapshot_everything() + -- compare with App.initialize_globals + local event = { + screen_top=deepcopy(Screen_top1), + selection=deepcopy(Selection1), + cursor=deepcopy(Cursor1), + current_drawing_mode=Drawing_mode, + previous_drawing_mode=Previous_drawing_mode, + zoom=Zoom, + lines={}, + -- no filename; undo history is cleared when filename changes + } + -- deep copy lines without cached stuff like text fragments + for _,line in ipairs(Lines) do + if line.mode == 'text' then + table.insert(event.lines, {mode='text', data=line.data}) + elseif line.mode == 'drawing' then + local points=deepcopy(line.points) +--? print('copying', line.points, 'with', #line.points, 'points into', points) + local shapes=deepcopy(line.shapes) +--? print('copying', line.shapes, 'with', #line.shapes, 'shapes into', shapes) + table.insert(event.lines, {mode='drawing', y=line.y, h=line.h, points=points, shapes=shapes, pending={}}) +--? table.insert(event.lines, {mode='drawing', y=line.y, h=line.h, points=deepcopy(line.points), shapes=deepcopy(line.shapes), pending={}}) + else + print(line.mode) + assert(false) + end + end + return event +end + +-- https://stackoverflow.com/questions/640642/how-do-you-copy-a-lua-table-by-value/26367080#26367080 +function deepcopy(obj, seen) + if type(obj) ~= 'table' then return obj end + if seen and seen[obj] then return seen[obj] end + local s = seen or {} + local result = setmetatable({}, getmetatable(obj)) + s[obj] = result + for k,v in pairs(obj) do + result[deepcopy(k, s)] = deepcopy(v, s) + end + return result +end |