1 files changed, 657 insertions, 0 deletions

diff --git a/unit_trace/viz/graph.py b/unit_trace/viz/graph.py
new file mode 100644
index 0000000..6982e7c
--- /dev/null
+++ b/unit_trace/viz/graph.py
@@ -0,0 +1,657 @@
+import util
+import schedule
+from format import *
+from canvas import *
+
+"""The higher-level components of the rendering engine. The graph classes deal with more abstract dimensions
+than the canvas classes (time and task/cpu number rather than plain coordinates). Also, graphs know how to
+update themselves, unlike the Canvas which can only overwrite itself."""
+
+class Graph(object):
+    DEF_BAR_PLIST = [Pattern([(0.0, 0.9, 0.9)]), Pattern([(0.9, 0.3, 0.0)]), Pattern([(0.9, 0.7, 0.0)]),
+                     Pattern([(0.0, 0.0, 0.8)]), Pattern([(0.0, 0.2, 0.9)]), Pattern([(0.0, 0.6, 0.6)]),
+                     Pattern([(0.75, 0.75, 0.75)])]
+    DEF_ITEM_CLIST = [(0.3, 0.0, 0.0), (0.0, 0.3, 0.0), (0.0, 0.0, 0.3), (0.3, 0.3, 0.0), (0.0, 0.3, 0.3),
+                      (0.3, 0.0, 0.3)]
+    
+    def __init__(self, CanvasType, surface, start_time, end_time, y_item_list, attrs=GraphFormat(),
+                 item_clist=DEF_ITEM_CLIST, bar_plist=DEF_BAR_PLIST):
+        # deal with possibly blank schedules
+        if start_time is None:
+            start_time = 0
+        if end_time is None:
+            end_time = 0
+         
+        if start_time > end_time:
+            raise ValueError("Litmus is not a time machine")
+            
+        self.attrs = attrs
+        self.start_time = start_time
+        self.end_time = end_time
+        self.y_item_list = y_item_list
+        self.num_maj = int(math.ceil((self.end_time - self.start_time) * 1.0 / self.attrs.time_per_maj)) + 1
+    
+        width = self.num_maj * self.attrs.maj_sep + GraphFormat.X_AXIS_MEASURE_OFS + GraphFormat.WIDTH_PAD
+        height = (len(self.y_item_list) + 1) * self.attrs.y_item_size + GraphFormat.HEIGHT_PAD
+
+        # We need to stretch the width in order to fit the y-axis labels. To do this we need
+        # the extents information, but we haven't set up a surface yet, so we just use a
+        # temporary one.
+        extra_width = 0.0
+        dummy_surface = surface.__class__()
+        dummy_surface.renew(10, 10)
+        
+        dummy_surface.ctx.select_font_face(self.attrs.item_fopts.name, cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_BOLD)
+        dummy_surface.ctx.set_font_size(self.attrs.item_fopts.size)
+        for item in self.y_item_list:
+            dummy_surface.ctx.set_source_rgb(0.0, 0.0, 0.0)
+            te = dummy_surface.ctx.text_extents(item)
+            cur_width = te[2]
+            if cur_width > extra_width:
+                extra_width = cur_width
+            
+        width += extra_width
+        
+        self.origin = (extra_width + GraphFormat.WIDTH_PAD / 2.0, height - GraphFormat.HEIGHT_PAD / 2.0)
+        
+        self.width = width
+        self.height = height
+        
+        #if surface.ctx is None:
+        #    surface.renew(width, height)
+        
+        self.canvas = CanvasType(width, height, item_clist, bar_plist, surface)
+    
+    def get_selected_regions(self, real_x, real_y, width, height):
+        return self.canvas.get_selected_regions(real_x, real_y, width, height)
+                
+    def get_width(self):
+        return self.width
+        
+    def get_height(self):
+        return self.height
+    
+    def get_origin(self):
+        return self.origin
+        
+    def get_attrs(self):
+        return self.attrs
+    
+    def add_sel_region(self, region):
+        self.canvas.add_sel_region(region)
+    
+    def get_sel_region(self, event):
+        return self.canvas.get_sel_region(event)
+    
+    def has_sel_region(self, event):
+        return self.canvas.has_sel_region(event)
+            
+    def update_view(self, x, y, width, height, scale, ctx):
+        """Proxy into the surface's pan."""
+        self.canvas.surface.pan(x, y, width, height)
+        self.canvas.set_scale(scale)
+        self.canvas.surface.change_ctx(ctx)
+    
+    def _recomp_min_max(self, start_time, end_time, start_item, end_item):
+        if self.min_time is None or start_time < self.min_time:
+            self.min_time = start_time
+        if self.max_time is None or end_time > self.max_time:
+            self.max_time = end_time
+        if self.min_item is None or start_item < self.min_item:
+            self.min_item = start_item
+        if self.max_item is None or end_item > self.max_item:
+            self.max_item = end_item
+        
+    def _get_time_xpos(self, time):
+        """get x so that x is at instant ``time'' on the graph"""
+        return self.origin[0] + GraphFormat.X_AXIS_MEASURE_OFS + 1.0 * (time - self.start_time) / self.attrs.time_per_maj * self.attrs.maj_sep
+    
+    def _get_item_ypos(self, item_no):
+        """get y so that y is where the top of a bar would be in item #n's area"""
+        return self.origin[1] - self._get_y_axis_height() + self.attrs.y_item_size * (item_no + 0.5 - GraphFormat.BAR_SIZE_FACTOR / 2.0)     
+    
+    def _get_bar_width(self, start_time, end_time):
+        return 1.0 * (end_time - start_time) / self.attrs.time_per_maj * self.attrs.maj_sep
+    
+    def _get_bar_height(self):
+        return self.attrs.y_item_size * GraphFormat.BAR_SIZE_FACTOR
+    
+    def _get_mini_bar_height(self):
+        return self.attrs.y_item_size * GraphFormat.MINI_BAR_SIZE_FACTOR
+        
+    def _get_mini_bar_ofs(self):
+        return self.attrs.y_item_size * (GraphFormat.MINI_BAR_SIZE_FACTOR + GraphFormat.BAR_MINI_BAR_GAP_FACTOR)
+        
+    def _get_y_axis_height(self):
+        return (len(self.y_item_list) + 1) * self.attrs.y_item_size
+    
+    def _get_bottom_tick(self, time):
+        return int(math.floor((time - self.start_time) / self.attrs.time_per_maj))
+    
+    def _get_top_tick(self, time):
+        return int(math.ceil((time - self.start_time) / self.attrs.time_per_maj))
+        
+    def get_surface(self):
+        """Gets the underlying surface."""
+        return self.canvas.get_surface()
+    
+    def xcoor_to_time(self, x):
+        #x = self.origin[0] + GraphFormat.X_AXIS_MEASURE_OFS + (time - self.start) / self.attrs.time_per_maj * self.attrs.maj_sep
+        return (x - self.origin[0] - GraphFormat.X_AXIS_MEASURE_OFS) / self.attrs.maj_sep \
+                * self.attrs.time_per_maj + self.start_time
+    
+    def ycoor_to_item_no(self, y):
+        return int((y - self.origin[1] + self._get_y_axis_height()) // self.attrs.y_item_size) 
+    
+    def get_offset_params(self, real_x, real_y, width, height):
+        x_start, y_start = self.canvas.surface.get_virt_coor_unscaled(real_x, real_y)
+        x_end, y_end = self.canvas.surface.get_virt_coor_unscaled(real_x + width, real_y + height)
+        
+        start_time = self.xcoor_to_time(x_start)
+        end_time = self.xcoor_to_time(x_end)
+        
+        start_item = self.ycoor_to_item_no(y_start)
+        end_item = 1 + self.ycoor_to_item_no(y_end)
+        
+        return (start_time, end_time, start_item, end_item)
+    
+    def draw_skeleton(self, start_time, end_time, start_item, end_item):
+        self.draw_grid_at_time(start_time, end_time, start_item, end_item)
+        self.draw_x_axis_with_labels_at_time(start_time, end_time)
+        self.draw_y_axis_with_labels()
+            
+    def render_surface(self, sched, regions, selectable=False):
+        raise NotImplementedError
+    
+    def render_all(self, schedule):
+        raise NotImplementedError
+    
+    def get_events_to_render(self, sched, regions, selectable=False):
+        raise NotImplementedError
+        
+    def render_surface(self, sched, regions, selectable=False):
+        if not selectable:
+            self.canvas.whiteout()
+        else:
+            self.canvas.clear_selectable_regions()
+        self.render_events(self.get_events_to_render(sched, regions, selectable), selectable)
+        
+    def render_events(self, events, selectable=False):
+        for layer in Canvas.LAYERS:
+            prev_events = {}
+            if layer in events:
+                for event in events[layer]:
+                    event.render(self, layer, prev_events, selectable)
+                                        
+    def draw_axes(self, x_axis_label, y_axis_label):
+        """Draws and labels the axes according to the parameters that we were initialized
+        with."""    
+        self.draw_grid_at_time(self.start_time, self.end_time, 0, len(self.attrs.y_item_list) - 1)
+        
+        self.canvas.draw_x_axis(self.origin[0], self.origin[1], self.num_maj, self.attrs.maj_sep, self.attrs.min_per_maj)
+        self.canvas.draw_y_axis(self.origin[0], self.origin[1], self._get_y_axis_height())
+        self.canvas.draw_x_axis_labels(self.origin[0], self.origin[1], 0, self.num_maj - 1,\
+                                self.attrs.maj_sep, self.attrs.min_per_maj, self.start_time, \
+                                self.attrs.time_per_maj, self.attrs.show_min, self.attrs.majfopts, self.attrs.minfopts)
+        self.canvas.draw_y_axis_labels(self.origin[0], self.origin[1], self._get_y_axis_height(), self.y_item_list, \
+                                       self.attrs.y_item_size, self.attrs.item_fopts)
+    
+    def draw_grid_at_time(self, start_time, end_time, start_item, end_item):
+        """Draws the grid, but only in a certain time and item range."""
+        start_tick = max(0, self._get_bottom_tick(start_time))
+        end_tick = min(self.num_maj - 1, self._get_top_tick(end_time))
+        
+        start_item = max(0, start_item)
+        end_item = min(len(self.y_item_list), end_item)
+        
+        self.canvas.draw_grid(self.origin[0], self.origin[1], self._get_y_axis_height(),
+                              start_tick, end_tick, start_item, end_item, self.attrs.maj_sep, self.attrs.y_item_size, \
+                              self.attrs.min_per_maj, True)
+    
+    def draw_x_axis_with_labels_at_time(self, start_time, end_time):
+        start_tick = max(0, self._get_bottom_tick(start_time))
+        end_tick = min(self.num_maj - 1, self._get_top_tick(end_time))
+                                      
+        self.canvas.draw_x_axis(self.origin[0], self.origin[1], start_tick, end_tick, \
+                                self.attrs.maj_sep, self.attrs.min_per_maj)
+        self.canvas.draw_x_axis_labels(self.origin[0], self.origin[1], start_tick, \
+                                end_tick, self.attrs.maj_sep, self.attrs.min_per_maj,
+                                self.start_time + start_tick * self.attrs.time_per_maj,
+                                self.attrs.time_per_maj, False)
+                                
+    def draw_y_axis_with_labels(self):
+        self.canvas.draw_y_axis(self.origin[0], self.origin[1], self._get_y_axis_height())
+        self.canvas.draw_y_axis_labels(self.origin[0], self.origin[1], self._get_y_axis_height(), \
+                                       self.y_item_list, self.attrs.y_item_size)
+            
+    def draw_suspend_triangle_at_time(self, time, task_no, cpu_no, selected=False):
+        """Draws a suspension symbol for a dcertain task at an instant in time."""
+        raise NotImplementedError
+    
+    def add_sel_suspend_triangle_at_time(self, time, task_no, cpu_no, event):
+        """Same as above, except instead of drawing adds a selectable region at
+        a certain time."""
+        raise NotImplementedError
+    
+    def draw_resume_triangle_at_time(self, time, task_no, cpu_no, selected=False):
+        """Draws a resumption symbol for a certain task at an instant in time."""
+        raise NotImplementedError
+    
+    def add_sel_resume_triangle_at_time(self, time, task_no, cpu_no, event):
+        """Same as above, except instead of drawing adds a selectable region at
+        a certain time."""
+        raise NotImplementedError
+            
+    def draw_completion_marker_at_time(self, time, task_no, cpu_no, selected=False):
+        """Draws a completion marker for a certain task at an instant in time."""
+        raise NotImplementedError
+    
+    def add_sel_completion_marker_at_time(self, time, task_no, cpu_no, event):
+        """Same as above, except instead of drawing adds a selectable region at
+        a certain time."""
+        raise NotImplementedError
+            
+    def draw_release_arrow_at_time(self, time, task_no, job_no, selected=False):
+        """Draws a release arrow at a certain time for some task and job"""
+        raise NotImplementedError
+    
+    def add_sel_release_arrow_at_time(self, time, task_no, event):
+        """Same as above, except instead of drawing adds a selectable region at
+        a certain time."""
+        raise NotImplementedError
+            
+    def draw_deadline_arrow_at_time(self, time, task_no, job_no, selected=False):
+        """Draws a deadline arrow at a certain time for some task and job"""
+        raise NotImplementedError
+    
+    def add_sel_deadline_arrow_at_time(self, time, task_no, event):
+        """Same as above, except instead of drawing adds a selectable region at
+        a certain time."""
+        raise NotImplementedError
+        
+    def draw_bar_at_time(self, start_time, end_time, task_no, cpu_no, job_no=None, clip_side=None):
+        """Draws a bar over a certain time period for some task, optionally labelling it."""
+        raise NotImplementedError
+        
+    def add_sel_bar_at_time(self, start_time, end_time, task_no, cpu_no, event):
+        """Same as above, except instead of drawing adds a selectable region at
+        a certain time."""
+        raise NotImplementedError
+    
+    def draw_mini_bar_at_time(self, start_time, end_time, task_no, cpu_no, clip_side=None, job_no=None):
+        """Draws a mini bar over a certain time period for some task, optionally labelling it."""
+        raise NotImplementedError
+        
+    def add_sel_mini_bar_at_time(self, start_time, end_time, task_no, cpu_no, event):
+        """Same as above, except instead of drawing adds a selectable region at
+        a certain time."""
+        raise NotImplementedError
+            
+class TaskGraph(Graph):
+    def get_events_to_render(self, sched, regions, selectable=False):
+        slots = {}
+        
+        self.min_time, self.max_time, self.min_item, self.max_item = None, None, None, None  
+        for region in regions:
+            x, y, width, height = region
+            start_time, end_time, start_item, end_item = self.get_offset_params(x, y, width, height)
+            self._recomp_min_max(start_time, end_time, start_item, end_item)
+            
+            sched.get_time_slot_array().get_slots(slots,
+                        start_time, end_time, start_item, end_item,
+                        schedule.TimeSlotArray.TASK_LIST)
+
+        
+        if not selectable:
+            self.draw_skeleton(self.min_time, self.max_time,
+                               self.min_item, self.max_item)
+        
+        events_to_render = {}
+        for layer in Canvas.LAYERS:
+            events_to_render[layer] = {}
+        
+        for event in sched.get_time_slot_array().get_events(slots,
+                schedule.TimeSlotArray.TASK_LIST,
+                schedule.EVENT_LIST):
+            events_to_render[event.get_layer()][event] = None    
+        
+        return events_to_render
+        
+    def draw_suspend_triangle_at_time(self, time, task_no, cpu_no, selected=False):
+        height = self._get_bar_height() * GraphFormat.BLOCK_TRIANGLE_FACTOR
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(task_no) + self._get_bar_height() / 2.0 - height / 2.0
+        self.canvas.draw_suspend_triangle(x, y, height, selected)
+    
+    def add_sel_suspend_triangle_at_time(self, time, task_no, cpu_no, event):
+        height = self._get_bar_height() * GraphFormat.BLOCK_TRIANGLE_FACTOR
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(task_no) + self._get_bar_height() / 2.0 - height / 2.0
+        
+        self.canvas.add_sel_suspend_triangle(x, y, height, event)
+        
+    def draw_resume_triangle_at_time(self, time, task_no, cpu_no, selected=False):
+        height = self._get_bar_height() * GraphFormat.BLOCK_TRIANGLE_FACTOR
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(task_no) + self._get_bar_height() / 2.0 - height / 2.0
+        
+        self.canvas.draw_resume_triangle(x, y, height, selected)
+    
+    def add_sel_resume_triangle_at_time(self, time, task_no, cpu_no, event):
+        height = self._get_bar_height() * GraphFormat.BLOCK_TRIANGLE_FACTOR
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(task_no) + self._get_bar_height() / 2.0 - height / 2.0
+        
+        self.canvas.add_sel_resume_triangle(x, y, height, event)
+        
+    def draw_completion_marker_at_time(self, time, task_no, cpu_no, selected=False):
+        height = self._get_bar_height() * GraphFormat.COMPLETION_MARKER_FACTOR
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(task_no) + self._get_bar_height() - height
+        
+        self.canvas.draw_completion_marker(x, y, height, selected)
+    
+    def add_sel_completion_marker_at_time(self, time, task_no, cpu_no, event):
+        height = self._get_bar_height() * GraphFormat.COMPLETION_MARKER_FACTOR
+        
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(task_no) + self._get_bar_height() - height
+        
+        self.canvas.add_sel_completion_marker(x, y, height, event)
+            
+    def draw_release_arrow_at_time(self, time, task_no, job_no=None, selected=False):
+        height = self._get_bar_height() * GraphFormat.BIG_ARROW_FACTOR
+        
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(task_no) + self._get_bar_height() - height
+        
+        self.canvas.draw_release_arrow_big(x, y, height, selected)
+    
+    def add_sel_release_arrow_at_time(self, time, task_no, event):
+        height = self._get_bar_height() * GraphFormat.BIG_ARROW_FACTOR
+        
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(task_no) + self._get_bar_height() - height
+        
+        self.canvas.add_sel_release_arrow_big(x, y, height, event)
+        
+    def draw_deadline_arrow_at_time(self, time, task_no, job_no=None, selected=False):
+        height = self._get_bar_height() * GraphFormat.BIG_ARROW_FACTOR
+        
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(task_no)
+        
+        self.canvas.draw_deadline_arrow_big(x, y, height, selected)
+    
+    def add_sel_deadline_arrow_at_time(self, time, task_no, event):
+        height = self._get_bar_height() * GraphFormat.BIG_ARROW_FACTOR
+        
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(task_no)
+        
+        self.canvas.add_sel_deadline_arrow_big(x, y, height, event)
+        
+    def draw_bar_at_time(self, start_time, end_time, task_no, cpu_no, job_no=None, clip_side=None, selected=False):
+        if start_time > end_time:
+            raise ValueError("Litmus is not a time machine")
+            
+        x = self._get_time_xpos(start_time)
+        y = self._get_item_ypos(task_no)
+        width = self._get_bar_width(start_time, end_time)
+        height = self._get_bar_height()
+        
+        self.canvas.draw_bar(x, y, width, height, cpu_no, clip_side, selected)
+        
+        # if a job number is specified, we want to draw a superscript and subscript for the task and job number, respectively
+        if job_no is not None:
+            x += GraphFormat.BAR_LABEL_OFS
+            y += self.attrs.y_item_size * GraphFormat.BAR_SIZE_FACTOR / 2.0
+            self.canvas.draw_label_with_sscripts('T', str(task_no), str(job_no), x, y, \
+                GraphFormat.DEF_FOPTS_BAR, GraphFormat.DEF_FOPTS_BAR_SSCRIPT, AlignMode.LEFT, AlignMode.CENTER)
+    
+    def add_sel_bar_at_time(self, start_time, end_time, task_no, cpu_no, event):
+        if start_time > end_time:
+            raise ValueError("Litmus is not a time machine")
+            
+        x = self._get_time_xpos(start_time)
+        y = self._get_item_ypos(task_no)
+        width = self._get_bar_width(start_time, end_time)
+        height = self._get_bar_height()
+        
+        self.canvas.add_sel_bar(x, y, width, height, event)
+    
+    def draw_mini_bar_at_time(self, start_time, end_time, task_no, cpu_no, job_no=None, clip_side=None, selected=False):
+        if start_time > end_time:
+            raise ValueError("Litmus is not a time machine")
+            
+        x = self._get_time_xpos(start_time)
+        y = self._get_item_ypos(task_no) - self._get_mini_bar_ofs()
+        width = self._get_bar_width(start_time, end_time)
+        height = self._get_mini_bar_height()
+        
+        self.canvas.draw_mini_bar(x, y, width, height, Canvas.NULL_PATTERN, clip_side, selected)
+        
+        if job_no is not None:
+            x += GraphFormat.MINI_BAR_LABEL_OFS
+            y += self.attrs.y_item_size * GraphFormat.MINI_BAR_SIZE_FACTOR / 2.0
+            self.canvas.draw_label_with_sscripts('T', str(task_no), str(job_no), x, y, \
+                GraphFormat.DEF_FOPTS_MINI_BAR, GraphFormat.DEF_FOPTS_MINI_BAR_SSCRIPT, AlignMode.LEFT, AlignMode.CENTER)
+                
+    def add_sel_mini_bar_at_time(self, start_time, end_time, task_no, cpu_no, event):
+        x = self._get_time_xpos(start_time)
+        y = self._get_item_ypos(task_no) - self._get_mini_bar_ofs()
+        width = self._get_bar_width(start_time, end_time)
+        height = self._get_mini_bar_height()
+        
+        self.canvas.add_sel_mini_bar(x, y, width, height, event)
+        
+class CpuGraph(Graph):
+    def get_events_to_render(self, sched, regions, selectable=False):
+        BOTTOM_EVENTS = [schedule.ReleaseEvent, schedule.DeadlineEvent, schedule.InversionStartEvent,
+                     schedule.InversionEndEvent, schedule.InversionDummy]
+        TOP_EVENTS = [schedule.SuspendEvent, schedule.ResumeEvent, schedule.CompleteEvent,
+                  schedule.SwitchAwayEvent, schedule.SwitchToEvent, schedule.IsRunningDummy]
+        
+        if not regions:
+            return {}
+            
+        top_slots = {}
+        bottom_slots = {}
+        
+        self.min_time, self.max_time, self.min_item, self.max_item = None, None, None, None
+        for region in regions:
+            x, y, width, height = region
+            start_time, end_time, start_item, end_item = self.get_offset_params(x, y, width, height)
+            self._recomp_min_max(start_time, end_time, start_item, end_item)
+            
+            sched.get_time_slot_array().get_slots(top_slots,
+                        start_time, end_time, start_item, end_item,
+                        schedule.TimeSlotArray.CPU_LIST)
+        
+            if end_item >= len(self.y_item_list):
+                # we are far down enough that we should render the releases and deadlines and inversions,
+                # which appear near the x-axis
+                sched.get_time_slot_array().get_slots(bottom_slots,
+                        start_time, end_time, 0, sched.get_num_cpus(),
+                        schedule.TimeSlotArray.CPU_LIST)
+        
+        if not selectable:
+            self.draw_skeleton(self.min_time, self.max_time,
+                               self.min_item, self.max_item)
+        
+        events_to_render = {}
+        for layer in Canvas.LAYERS:
+            events_to_render[layer] = {}
+        
+        for event in sched.get_time_slot_array().get_events(top_slots,
+                schedule.TimeSlotArray.CPU_LIST,
+                TOP_EVENTS):
+            events_to_render[event.get_layer()][event] = None  
+        for event in sched.get_time_slot_array().get_events(bottom_slots,
+                schedule.TimeSlotArray.CPU_LIST,
+                BOTTOM_EVENTS):
+            events_to_render[event.get_layer()][event] = None  
+        
+        return events_to_render
+                
+    def render(self, schedule, start_time=None, end_time=None):
+        if end_time < start_time:
+            raise ValueError('start must be less than end')
+            
+        if start_time is None:
+            start_time = self.start
+        if end_time is None:
+            end_time = self.end
+        start_slot = self.get_time_slot(start_time)
+        end_slot = min(len(self.time_slots), self.get_time_slot(end_time) + 1)
+        
+        for layer in Canvas.LAYERS:
+            prev_events = {}
+            for i in range(start_slot, end_slot):
+                for event in self.time_slots[i]:
+                    event.render(graph, layer, prev_events)
+                    
+    def draw_suspend_triangle_at_time(self, time, task_no, cpu_no, selected=False):
+        height = self._get_bar_height() * GraphFormat.BLOCK_TRIANGLE_FACTOR
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(cpu_no) + self._get_bar_height() / 2.0 - height / 2.0
+        self.canvas.draw_suspend_triangle(x, y, height, selected)
+    
+    def add_sel_suspend_triangle_at_time(self, time, task_no, cpu_no, event):
+        height = self._get_bar_height() * GraphFormat.BLOCK_TRIANGLE_FACTOR
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(cpu_no) + self._get_bar_height() / 2.0 - height / 2.0
+        
+        self.canvas.add_sel_suspend_triangle(x, y, height, event)
+        
+    def draw_resume_triangle_at_time(self, time, task_no, cpu_no, selected=False):
+        height = self._get_bar_height() * GraphFormat.BLOCK_TRIANGLE_FACTOR
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(cpu_no) + self._get_bar_height() / 2.0 - height / 2.0
+        
+        self.canvas.draw_resume_triangle(x, y, height, selected)
+    
+    def add_sel_resume_triangle_at_time(self, time, task_no, cpu_no, event):
+        height = self._get_bar_height() * GraphFormat.BLOCK_TRIANGLE_FACTOR
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(cpu_no) + self._get_bar_height() / 2.0 - height / 2.0
+        
+        self.canvas.add_sel_resume_triangle(x, y, height, event)
+        
+    def draw_completion_marker_at_time(self, time, task_no, cpu_no, selected=False):
+        height = self._get_bar_height() * GraphFormat.COMPLETION_MARKER_FACTOR
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(cpu_no) + self._get_bar_height() - height
+        
+        self.canvas.draw_completion_marker(x, y, height, selected)
+    
+    def add_sel_completion_marker_at_time(self, time, task_no, cpu_no, event):
+        height = self._get_bar_height() * GraphFormat.COMPLETION_MARKER_FACTOR
+        
+        x = self._get_time_xpos(time)
+        y = self._get_item_ypos(cpu_no) + self._get_bar_height() - height
+        
+        self.canvas.add_sel_completion_marker(x, y, height, event)
+            
+    def draw_release_arrow_at_time(self, time, task_no, job_no=None, selected=False):
+        if job_no is None and task_no is not None:
+            raise ValueError("Must specify a job number along with the task number")
+            
+        height = self._get_bar_height() * GraphFormat.SMALL_ARROW_FACTOR
+        
+        x = self._get_time_xpos(time)
+        y = self.origin[1] - height
+        
+        self.canvas.draw_release_arrow_small(x, y, height, selected)
+    
+        if task_no is not None:
+            y -= GraphFormat.ARROW_LABEL_OFS
+            self.canvas.draw_label_with_sscripts('T', str(task_no), str(job_no), x, y, \
+                                          GraphFormat.DEF_FOPTS_ARROW, GraphFormat.DEF_FOPTS_ARROW_SSCRIPT, \
+                                          AlignMode.CENTER, AlignMode.BOTTOM)
+    
+    def add_sel_release_arrow_at_time(self, time, task_no, event):
+        height = self._get_bar_height() * GraphFormat.SMALL_ARROW_FACTOR
+        
+        x = self._get_time_xpos(time)
+        y = self.origin[1] - height
+        
+        self.canvas.add_sel_release_arrow_small(x, y, height, event)
+            
+    def draw_deadline_arrow_at_time(self, time, task_no, job_no=None, selected=False):
+        if job_no is None and task_no is not None:
+            raise ValueError("Must specify a job number along with the task number")
+            
+        height = self._get_bar_height() * GraphFormat.SMALL_ARROW_FACTOR
+        
+        x = self._get_time_xpos(time)
+        y = self.origin[1] - height
+        
+        self.canvas.draw_deadline_arrow_small(x, y, height, selected)
+    
+        if task_no is not None:
+            y -= GraphFormat.ARROW_LABEL_OFS
+            self.canvas.draw_label_with_sscripts('T', str(task_no), str(job_no), x, y, \
+                                          GraphFormat.DEF_FOPTS_ARROW, GraphFormat.DEF_FOPTS_ARROW_SSCRIPT, \
+                                          AlignMode.CENTER, AlignMode.BOTTOM)
+    
+    def add_sel_deadline_arrow_at_time(self, time, task_no, event):
+        height = self._get_bar_height() * GraphFormat.SMALL_ARROW_FACTOR
+        
+        x = self._get_time_xpos(time)
+        y = self.origin[1] - height
+        
+        self.canvas.add_sel_deadline_arrow_small(x, y, height, event)
+        
+    def draw_bar_at_time(self, start_time, end_time, task_no, cpu_no, job_no=None, clip_side=None, selected=False):
+        if start_time > end_time:
+            raise ValueError("Litmus is not a time machine")
+            
+        x = self._get_time_xpos(start_time)
+        y = self._get_item_ypos(cpu_no)
+        width = self._get_bar_width(start_time, end_time)
+        height = self._get_bar_height()
+        
+        self.canvas.draw_bar(x, y, width, height, task_no, clip_side, selected)
+        
+        # if a job number is specified, we want to draw a superscript and subscript for the task and job number, respectively
+        if job_no is not None:
+            x += GraphFormat.BAR_LABEL_OFS
+            y += self.attrs.y_item_size * GraphFormat.BAR_SIZE_FACTOR / 2.0
+            self.canvas.draw_label_with_sscripts('T', str(task_no), str(job_no), x, y, \
+                                                 GraphFormat.DEF_FOPTS_BAR, GraphFormat.DEF_FOPTS_BAR_SSCRIPT, \
+                                                 AlignMode.LEFT, AlignMode.CENTER)
+    
+    def add_sel_bar_at_time(self, start_time, end_time, task_no, cpu_no, event):
+        x = self._get_time_xpos(start_time)
+        y = self._get_item_ypos(cpu_no)
+        width = self._get_bar_width(start_time, end_time)
+        height = self._get_bar_height()
+        
+        self.canvas.add_sel_bar(x, y, width, height, event)
+    
+    def draw_mini_bar_at_time(self, start_time, end_time, task_no, cpu_no, job_no=None, clip_side=None, selected=False):
+        if start_time > end_time:
+            raise ValueError("Litmus is not a time machine")
+            
+        x = self._get_time_xpos(start_time)
+        y = self._get_item_ypos(len(self.y_item_list))
+        width = self._get_bar_width(start_time, end_time)
+        height = self._get_mini_bar_height()
+        
+        self.canvas.draw_mini_bar(x, y, width, height, task_no, clip_side, selected)
+        
+        if job_no is not None:
+            x += GraphFormat.MINI_BAR_LABEL_OFS
+            y += self.attrs.y_item_size * GraphFormat.MINI_BAR_SIZE_FACTOR / 2.0
+            self.canvas.draw_label_with_sscripts('T', str(task_no), str(job_no), x, y, \
+                GraphFormat.DEF_FOPTS_MINI_BAR, GraphFormat.DEF_FOPTS_MINI_BAR_SSCRIPT, AlignMode.LEFT, AlignMode.CENTER)
+                
+    def add_sel_mini_bar_at_time(self, start_time, end_time, task_no, cpu_no, event):
+        x = self._get_time_xpos(start_time)
+        y = self._get_item_ypos(len(self.y_item_list))
+        width = self._get_bar_width(start_time, end_time)
+        height = self._get_mini_bar_height()
+        
+        self.canvas.add_sel_mini_bar(x, y, width, height, event)
+