add breakpoints to view movement undo system

src/components/systems/view_controls.zig

@@ -51,23 +51,23 @@ pub const ViewAxisPosition = struct {
     }
 };
 
-pub const Command = struct {
-    view_id: Id,
-    action: union(enum) {
+pub const Command = union(enum) {
+    breakpoint,
     move_and_zoom: struct {
+        view_id: Id,
         before_x: RangeF64,
         before_y: RangeF64,
         x: RangeF64,
         y: RangeF64
-        }
     },
 
     fn apply(self: *const Command, system: *System) void {
         const project = system.project;
-        const view = project.views.get(self.view_id) orelse return;
 
-        switch (self.action) {
+        switch (self.*) {
+            .breakpoint => {},
             .move_and_zoom => |move_and_zoom| {
+                const view = project.views.get(move_and_zoom.view_id) orelse return;
                 const view_rect = &view.graph_opts;
                 view_rect.x_range = move_and_zoom.x;
                 view_rect.y_range = move_and_zoom.y;
@@ -78,10 +78,11 @@ pub const Command = struct {
 
     fn undo(self: *const Command, system: *System) void {
         const project = system.project;
-        const view = project.views.get(self.view_id) orelse return;
 
-        switch (self.action) {
+        switch (self.*) {
+            .breakpoint => {},
             .move_and_zoom => |move_and_zoom| {
+                const view = project.views.get(move_and_zoom.view_id) orelse return;
                 const view_rect = &view.graph_opts;
                 view_rect.x_range = move_and_zoom.before_x;
                 view_rect.y_range = move_and_zoom.before_y;
@@ -95,8 +96,9 @@ pub const CommandFrame = struct {
     commands: std.BoundedArray(Command, constants.max_views) = .{},
 
     fn findCommandByView(self: *CommandFrame, view_id: Id) ?*Command {
-        for (self.commands.slice()) |*command| {
-            if (command.view_id.eql(view_id)) {
+        const commands: []Command = self.commands.slice();
+        for (commands) |*command| {
+            if (command.* == .move_and_zoom and command.move_and_zoom.view_id.eql(view_id)) {
                 return command;
             }
         }
@@ -117,6 +119,16 @@ pub const CommandFrame = struct {
             command.undo(system);
         }
     }
+
+    fn hasBreakpoint(self: *const CommandFrame) bool {
+        const commands: []const Command = self.commands.constSlice();
+        for (commands) |*command| {
+            if (command.* == .breakpoint) {
+                return true;
+            }
+        }
+         return false;
+    }
 };
 
 pub const CommandFrameArray = std.BoundedArray(CommandFrame, 64);
@@ -146,6 +158,7 @@ fn pushCommandFrame(self: *System) *CommandFrame {
 
     var frame = self.undo_stack.addOneAssumeCapacity();
     frame.updated_at_ns = std.time.nanoTimestamp();
+    frame.commands.len = 0;
     return frame;
 }
 
@@ -157,9 +170,19 @@ fn lastCommandFrame(self: *System) ?*CommandFrame {
     return null;
 }
 
+pub fn pushBreakpoint(self: *System) void {
+    if (self.lastCommandFrame()) |last_frame| {
+        // No need to have 2 break points in a row
+        if (last_frame.hasBreakpoint()) {
+            return;
+        }
+    }
+
+    const frame = self.pushCommandFrame();
+    frame.commands.appendAssumeCapacity(.{ .breakpoint = {} });
+}
+
 pub fn pushViewMove(self: *System, view_id: Id, x_range: RangeF64, y_range: RangeF64) void {
-
-
     var frame: *CommandFrame = undefined;
     {
         var push_new_command = true;
@@ -204,8 +227,8 @@ pub fn pushViewMove(self: *System, view_id: Id, x_range: RangeF64, y_range: Rang
         if (frame.findCommandByView(id)) |prev_command| {
             command = prev_command;
 
-            command.action.move_and_zoom.x = x_range;
-            command.action.move_and_zoom.y = y_range;
+            command.move_and_zoom.x = x_range;
+            command.move_and_zoom.y = y_range;
         } else {
             const view = self.project.views.get(view_id) orelse continue;
             const view_rect = &view.graph_opts;
@@ -213,15 +236,13 @@ pub fn pushViewMove(self: *System, view_id: Id, x_range: RangeF64, y_range: Rang
             command = frame.commands.addOneAssumeCapacity();
 
             command.* = Command{
-                .view_id = id,
-                .action = .{
                 .move_and_zoom = .{
+                    .view_id = id,
                     .before_x = view_rect.x_range,
                     .before_y = view_rect.y_range,
                     .x = x_range,
                     .y = y_range
                 }
-                }
             };
         }
     }
@@ -240,11 +261,15 @@ pub fn pushViewMoveAxis(self: *System, view_id: Id, axis: UI.Axis, view_range: R
 }
 
 pub fn undoLastMove(self: *System) void {
-    const frame = self.undo_stack.popOrNull() orelse return;
-
+    while (self.undo_stack.popOrNull()) |frame| {
         frame.undo(self);
 
         self.last_applied_command = @min(self.last_applied_command, self.undo_stack.len);
+
+        if (!frame.hasBreakpoint()) {
+            break;
+        }
+    }
 }
 
 pub fn applyCommands(self: *System) void {

src/components/view.zig

@@ -100,6 +100,10 @@ fn showGraph(ctx: Context, view_id: Id) *UI.Box {
         ctx.view_controls.pushViewMove(view_id, view.available_x_range, view.available_y_range);
     }
 
+    if (signal.flags.contains(.left_released)) {
+        ctx.view_controls.pushBreakpoint();
+    }
+
     view.graph_cache.min_max_cache = app.getViewMinMaxCache(view_id);
 
     Graph.drawCached(&view.graph_cache, graph_box.persistent.size, view_opts.*, samples);