Drawings

Starting with Pine v4, indicators and strategies can create drawing objects on the chart. Three types of drawings are currently supported: label, line, and boxes. You will find one instance of each on the following chart:

The line, label, and box drawings in Pine v4 allow you to create indicators with more sophisticated visual components, e.g., pivot points, support/resistance levels, zig zag lines, labels containing dynamic text, etc.

In contrast to indicator plots (plots are created with functions plot, plotshape, plotchar), drawing objects can be created on historical bars as well as in the future, where no bars exist yet.

Creating drawings

Pine drawing objects are created with the label.new , line.new and box.new functions. While each function has many parameters, only the coordinates are mandatory. This is an example of code used to create a label on every bar:

The label is created with the parameters x=bar_index (the index of the current bar, bar_index) and y=high (high price of the current bar). When a new bar opens, a new label is created on it. Label objects created on previous bars stay on the chart until the indicator deletes them with an explicit call of the label.delete function, or until the automatic garbage collection process removes them.

Here is a modified version of the same script that shows the values of the x and y coordinates used to create the labels:

In this example labels are shown without background coloring (because of parameter style=label.style_none) but with dynamically created text (text="x=" + tostring(bar_index) + "\ny=" + tostring(high)) that prints label coordinates.

This is an example of code that creates line objects on a chart:

This is an example of code that creates box objects on a chart:

Calculation of drawings on bar updates

Drawing objects are subject to both commit and rollback actions, which affect the behavior of a script when it executes in the realtime bar, Execution model.

This script demonstrates the effect of rollback when running in the realtime bar:

While label.new creates a new label on every iteration of the script when price changes in the realtime bar, the most recent label created in the script’s previous iteration is also automatically deleted because of rollback before the next iteration. Only the last label created before the realtime bar’s close will be committed, and will thus persist.

Coordinates

Drawing objects are positioned on the chart according to x and y coordinates using a combination of 4 parameters: x, y, xloc and yloc. The value of xloc determines whether x will hold a bar index or time value. When yloc=yloc.price, y holds a price. y is ignored when yloc is set to yloc.abovebar or yloc.belowbar.

If a drawing object uses xloc.bar_index, then the x-coordinate is treated as an absolute bar index. The bar index of the current bar can be obtained from the built-in variable bar_index. The bar index of previous bars is bar_index[1], bar_index[2] and so on. xloc.bar_index is the default value for x-location parameters of both label and line drawings.

If a drawing object uses xloc.bar_time, then the x-coordinate is treated as a UNIX time in milliseconds. The start time of the current bar can be obtained from the built-in variable time. The bar time of previous bars is time[1], time[2] and so on. Time can also be set to an absolute time point with the timestamp function.

The xloc.bar_time and xloc.bar_index modes makes it possible to place a drawing object in the future, to the right of the current bar. For example:

This code places a label object in the future. X-location logic works identically for label, line, and box drawings.

Example for xloc.bar_index:

In contrast, y-location logic is different for label and line or box drawings. Pine’s line and box drawings always use yloc.price, so their y-coordinate is always treated as an absolute price value.

Label drawings have additional y-location values: yloc.abovebar and yloc.belowbar. When they are used, the value of the y parameter is ignored and the drawing object is placed above or below the bar.

Modifying drawings

A drawing object can be modified after its creation. The label.new, line.new, and box.new functions return a reference to the created drawing object (of type series label, series line and series box respectively). This reference can then be used as the first argument to the label.set_*, line.set_*, or box.set_* functions used to modify drawings. For example:

This simple script first creates a label on the current bar and then it writes a reference to it in a variable l. Then, depending on whether the current bar is rising or falling (condition close >= open), a number of label drawing properties are modified: text, color, y coordinate location (yloc) and label style.

One may notice that na is passed as the y argument to the label.new function call. The reason for this is that the example’s label uses either yloc.belowbar or yloc.abovebar y-locations, which don’t require a y value. A finite value for y is needed only if a label uses yloc.price.

The available setter functions for label drawings are:

• label.set_color — changes color of label
• label.set_size — changes size of label
• label.set_style — changes style of label
• label.set_text — changes text of label
• label.set_textcolor — changes color of text
• label.set_x — changes x-coordinate of label
• label.set_y — changes y-coordinate of label
• label.set_xy — changes both x and y coordinates of label
• label.set_xloc — changes x-location of label
• label.set_yloc — changes y-location of label
• label.set_tooltip — changes tooltip of label

The available setter functions for line drawings are:

• line.set_color — changes color of line
• line.set_extend — changes attribute that makes:
  • extend.none - a line segment
  • extend.left/extend.right - a ray
  • extend.both - an endless line
• line.set_style — changes [style of line](drawings_label_styles.interpreted-text role”ref”)
• line.set_width — changes width of line
• line.set_xloc — changes x-location of line (both x1 and x2)
• line.set_x1 — changes x1-coordinate of line
• line.set_y1 — changes y1-coordinate of line
• line.set_xy1 — changes both x1 and y1 coordinates of line
• line.set_x2 — changes x2-coordinate of line
• line.set_y2 — changes y2-coordinate of line
• line.set_xy2 — changes both x2 and y2 coordinates of line at once

The available setter functions for box drawings are:

• box.set_border_color — changes border color of the box
• box.set_bgcolor — changes background color of the box
• box.set_extend — changes attribute that makes:
  • extend.none - the horizontal borders start at the left border and end at the right border
  • extend.left/extend.right - the horizontal borders are extended indefinitely to the left/right of the box
  • extend.both - the horizontal borders are extended on both sides
• box.set_border_style — changes border style of the box
• box.set_border_width — changes border width of the box
• box.set_bottom — changes bottom coordinate of the box
• box.set_right — changes right coordinate of the box
• box.set_rightbottom — changes both right and bottom coordinates of the box at once
• box.set_top — changes top coordinate of the box
• box.set_left — changes left coordinate of the box
• box.set_lefttop — changes both left and top coordinates of the box at once

Label styles

Various styles can be applied to labels with either the label.new or label.set_style function:

Label style name	Label	Label with text
label.style_none
label.style_xcross
label.style_cross
label.style_triangleup
label.style_triangledown
label.style_flag
label.style_circle
label.style_arrowup
label.style_arrowdown
label.style_label_up
label.style_label_down
label.style_square
label.style_diamond

Line and box styles

Various styles can be applied to lines with either the line.new, box.new, line.set_style or box.set_border_style function:

Line style name	Line	Box
line.style_solid
line.style_dotted
line.style_dashed
line.style_arrow_left		Not supported
line.style_arrow_right		Not supported
line.style_arrow_both		Not supported

Deleting drawings

The label.delete, line.delete and box.delete functions delete label, line, or box drawing objects from the chart.

Here is Pine code that keeps just one label drawing object on the current bar, deleting the old ones:

On every new bar update of the “Last Bar Close 1” study, a new label object is created and written to variable l. Variable l is of type series label, so the [] operator is used to get the previous bar’s label object. That previous label is then passed to the label.delete function to delete it.

Functions label.delete and line.delete do nothing if the na value is used as an id, which makes code like the following unnecessary:

The previous script’s behavior can be reproduced using another approach:

When the study “Last Bar Close 2” gets a new bar update, variable l is still referencing the old label object created on the previous bar. This label is deleted with the label.delete(l) call. A new label is then created and its id saved to l. Using this approach there is no need to use the [] operator.

Note the use of the new Pine v4 var keyword. It creates variable l and initializes it with the na value only once. label.delete(l) would have no object to delete if it weren’t for the fact that l is initialized only once.

There is yet another way to achieve the same objective as in the two previous scripts, this time by modifying the label rather than deleting it:

Once again, the use of new var keyword is essential. It is what allows the label.new call to be executed only once, on the very first historical bar.

Examples of classic indicators

Pivot Points Standard

Pivot Points High/Low

Linear Regression

Zig Zag

Limits

Total number of drawings

Drawing objects consume server resources, which is why there is a limit to the total number of drawings per study or strategy. When too many drawings are created, old ones are automatically deleted by the Pine runtime, in a process referred to as garbage collection.

This code creates a drawing on every bar:

Scrolling the chart left, one will see there are no drawings after approximately 50 bars:

You can change the drawing limit to a value in range from 1 to 500 using the max_lines_count, max_labels_count, or max_boxes_count parameters for the study and strategy functions:

Bars count in future with xloc.bar_index

Objects positioned using xloc.bar_index cannot be drawn further than 500 bars into the future.

Additional securities

Pine code sometimes uses additional symbols and/or timeframes with the security function. Drawing functions can only be used in the main symbol’s context.

max_bars_back of time

Use of barstate.isrealtime in combination with drawings may sometimes produce unexpected results. This code’s intention, for example, is to ignore all historical bars and create a label drawing on the realtime bar:

It will, however, fail at runtime. The reason for the error is that Pine cannot determine the buffer size for historical values of the time plot, even though the time built-in variable isn’t mentioned in the code. This is due to the fact that the built-in variable bar_index uses the time series in its inner workings. Accessing the value of the bar index 10 bars back requires that the history buffer size of the time series be of size 10 or more.

In Pine, there is a mechanism that automaticaly detects the required historical buffer size for most cases. Autodetection works by letting Pine code access historical values any number of bars back for a limited duration. In this script’s case, the if barstate.isrealtime condition prevents any such accesses to occur, so the required historical buffer size cannot be inferred and the code fails.

The solution to this conundrum is to use the max_bars_back function to explicitly set the historical buffer size for the time series:

Such occurrences are confusing, but rare. In time, the Pine team hopes to eliminate them.