The Metrics Manager

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The Metrics Manager collects and reports on all metrics pertaining to the Blockly workspace. This guide describes the meaning of each set of metrics returned from the Metrics Manager. For more information on the Metrics Manager you can also watch our 2021 Metrics Deep Dive.

Metrics

Toolbox Metrics

workspace.getMetricsManager().getToolboxMetrics();

The toolbox metrics are composed of the height, width and position of a category toolbox. This does not include information on the flyout that is attached to the toolbox.

The Blockly workspace with arrows showing the width and height of the toolbox.

The position of the toolbox is of the type Blockly.utils.toolbox.Position.

Flyout Metrics

workspace.getMetricsManager().getFlyoutMetrics();

The flyout metrics are composed of the height, width and position of a flyout toolbox. It is important to note, that this is not the flyout that is attached to the category toolbox. This only pertains to flyout toolboxes as shown in the below photo.

The Blockly workspace with arrows showing the width and height of the flyout.

The position of the flyout is of the type Blockly.utils.toolbox.Position.

SVG Metrics

workspace.getMetricsManager().getSvgMetrics();

The SVG metrics are composed of the width and height of the workspace's parent SVG. For the main workspace, this is the SVG with the blocklySvg class. This SVG includes the visible workspace as well as the toolbox.

The Blockly workspace with a blue rectangle around it.

View Metrics

workspace.getMetricsManager().getViewMetrics(opt_getWorkspaceCoordinates);

The view metrics are composed of the height, width, top and left of the viewport. The viewport is the portion of the workspace that is visible. This does not include either type of toolbox.

The Blockly workspace with a blue rectangle around the area not including the toolbox.

The top left is relative to the workspace origin. As we drag around the workspace the top and left position of the viewport are updated.

The Blockly workspace with a blue rectangle around the area not including the toolbox, and an origin shown offset from the top left corner.

Absolute Metrics

workspace.getMetricsManager().getAbsoluteMetrics();

The absolute metrics are composed of the top and left offset of the viewport from the pareng SVG. Depending on where the toolbox is positioned on the workspace, this is usually the width or height of the toolbox.

The Blockly workspace with a blue line to the right of the toolbox and on top of the workspace. The Blockly workspace with a horizontal toolbox. There is a blue line on the left of the workspace and below the toolbox.

Content Metrics

workspace.getMetricsManager().getContentMetrics(opt_getWorkspaceCoordinates);

The content metrics are composed of the height, width, top and left of the bounding box around any blocks or workspace comments.

The Blockly workspace with a blue box around the contents of the workspace.

Scroll Metrics

workspace.getMetricsManager().getScrollMetrics(opt_getWorkspaceCoordinates);

The scroll metrics are composed of the height, width, top and left of the scrollable area. For a movable workspace, the scrollable area is the content area plus some padding.

The Blockly workspace with a large blue box surrounding it.

Coordinate Systems

By default, all metrics calculated by the Metrics Manager are returned as pixel coordinates. Where applicable there is the option to get certain metrics in workspace coordinates by passing in true to the metrics methods. For example, metricsManager.getViewMetrics(true).

workspaceCoordinate = pixelCoordinates / workspace.scale

Workspace coordinates are generally used for items that sit on the workspace, such as blocks and workspace comments. Workspace coordinates do not change as the user zooms in and out.

Overriding Metrics

Developers who wish to provide their own metrics for the workspace can register a substitute metrics manager object that implements the IMetricsManager interface or extends Blockly.MetricsManager.

An example of this can be found in the Continuous Toolbox plugin or in the Fixed Edges plugin.