add very basic undo/redo for move/scale/rotate

src/kiri/do.js

@@ -0,0 +1,156 @@
+/** Copyright Stewart Allen <sa@grid.space> -- All Rights Reserved */
+
+kiri.load(function(API) {
+    let stack = [];
+    let stpos = 0;
+
+    let event = API.event;
+    let moved = {x:0, y:0};
+    let msgid;
+
+    event.on("init-done", () => {
+        $('undo').onclick = undo;
+        $('redo').onclick = redo;
+    });
+
+    let undo = API.doit.undo = function() {
+        if (stpos) {
+            action(stack[--stpos].undo);
+        } else {
+            message('nothing to undo');
+        }
+    };
+
+    let redo = API.doit.redo = function() {
+        if (stpos < stack.length) {
+            action(stack[stpos++].redo);
+        } else {
+            message('nothing to redo');
+        }
+    };
+
+    let clear = API.doit.clear = function() {
+        stack = [];
+        stpos = 0;
+        moved = {x:0, y:0};
+        updateButtons();
+    };
+
+    function updateButtons() {
+        $('doit').style.display = stack.length ? '' : 'none';
+        $('undo').disabled = stpos === 0;
+        $('redo').disabled = stpos == stack.length;
+    }
+
+    function message(txt) {
+        if (msgid) {
+            API.hide.alert(msgid);
+        }
+        msgid = API.show.alert(txt);
+    }
+
+    function action(rec) {
+        switch (rec.type) {
+            case 'move':
+                for (let w of rec.widgets) {
+                    w._move(rec.dist.x, rec.dist.y, 0);
+                }
+                break;
+            case 'rotate':
+                for (let w of rec.widgets) {
+                    w.rotate(rec.x, rec.y, rec.z);
+                }
+                break;
+            case 'scale':
+                for (let w of rec.widgets) {
+                    w._scale(rec.x, rec.y, rec.z);
+                }
+                API.selection.update_info();
+                break;
+        }
+        API.space.update();
+        updateButtons();
+    }
+
+    function pushActions(ur) {
+        stack.length = stpos++;
+        stack.push(ur);
+        updateButtons();
+    }
+
+    event.on([
+        'platform.layout',
+        'widget.add',
+        'widget.delete'
+    ], (widget) => {
+        clear();
+    });
+
+    // selection event (store position)
+    event.on('widget.rotate', (rec) => {
+        let type = "rotate";
+        let {widget, x, y, z} = rec;
+        if (!(x || y || z)) {
+            return;
+        }
+        pushActions({
+            redo: {
+                type,
+                widgets: [ widget ],
+                x, y, z
+            },
+            undo: {
+                type,
+                widgets: [ widget ],
+                x: -x, y: -y, z: -z
+            }
+        })
+    });
+
+    event.on('selection.scale', (rec) => {
+        let [x, y, z] = rec;
+        // ignore scale close to 1
+        if (Math.abs(1 - (x * y * z)) < 0.0001) {
+            return;
+        }
+        let widgets = API.selection.widgets();
+        let type = "scale";
+        pushActions({
+            redo: {
+                type,
+                widgets,
+                x, y, z
+            },
+            undo: {
+                type,
+                widgets,
+                x: 1/x, y: 1/y, z: 1/z
+            }
+        });
+    });
+
+    // selection moved (accumulator)
+    event.on('selection.drag', (delta) => {
+        moved.x += delta.x;
+        moved.y += delta.y;
+    });
+
+    // move complete (store updated position)
+    event.on('mouse.drag.done', () => {
+        let widgets = API.selection.widgets();
+        let type = "move";
+        pushActions({
+            redo: {
+                type,
+                widgets,
+                dist: moved
+            },
+            undo: {
+                type,
+                widgets,
+                dist: {x: -moved.x, y: -moved.y}
+            }
+        });
+        moved = {x:0, y:0};
+    });
+});