Bluescape Image Handling on a Bluescape Wall Client

This technical note describes Bluescape document and image management on the Bluescape wall client. A Bluescape wall client renders workspaces on touch monitors via a controller, as opposed to the Bluescape browser client, which renders workspaces on a browser client (for example, Google Chrome), or the Bluescape Desktop App.

Bluescape wall clients optimize images to provide the best possible experience on
wall and browser clients. Bluescape image rendering behavior ties to the type and size of content viewed within a workspace.

For memory and performance reasons, Bluescape optimizes the following workspace elements:

  1. Images (for example, PNGs)
  2. Documents (for example, Microsoft Word)

The characteristics of these elements, like the size of an image or the number of pages in a document, are subject to Bluescape memory management routines. Immense scale or high levels of complexity Bluescape’s resource management processes may impact your workspaces in the manner described in the rest of this technical note.

Bluescape Wall Client Image and Document Processing Overview

Limitations in image and file sizes apply to two key Bluescape actions:

  • When uploading images or documents into workspaces
  • When sending workspaces to a wall client

Uploading Content

Bluescape users employ the Bluescape browser client to upload files to workspaces. Example files include JPEG and PNG images, Microsoft Word or PowerPoint files, and PDFs. Bluescape rasterizes documents like Word, PPT, and PDF files, resulting in one image per page or slide.

Thus, to a Bluescape workspace, everything uploaded as a file becomes an image subject to certain limitations and optimizations.

Note that documents or images obtained via a URL reference, like a Google Image or Microsoft SharePoint document, do not participate in the optimizations, nor are they subject to limitations described in this technical note; they are instead rendered in a workspace using an embedded browser.

Sending a Workspace to a Wall Client

When a workspace sends to a wall client, two optimization phases invoke:

  1. Optimizations applied to individual images
  2. Optimizations applied to all images on the wall client

With these principles in mind, let’s turn to optimizations applied to each action.

Bluescape Limits Applied While Uploading

Bluescape limits image and file sizes to prevent users from inadvertently overwhelming workspaces.

The maximum image resolution and file size that can be uploaded in a Bluescape workspace are:

  • 125-megapixels
  • 50MB

This limit enforces when a user uploads an image or document into a workspace. Especially in regard to image resolutions, these are generous limits allowing for extraordinarily rich, complex imagery to be stored within Bluescape for later downloads.

Bluescape Limits Applied When a Workspace Sends to a Wall Client

Optimizations Applied to each image

When a workspace sends to a Bluescape wall client, Bluescape applies the
following memory conservation constraints to images to conserve memory and ensure the best performance.

  • 12 megapixels per image maximum
  • 16,384 pixels maximum in either width or height

Recall that uploaded documents rasterize, and the resulting images representing each page (or slide) participate in this process.

Bluescape Wall Client Image Adjustments

When a workspace sends to a Bluescape wall client, Bluescape memory management routines will reduce images within the workspace that are larger than 12 megapixels or greater than 16,384 pixels in either width or height.

The algorithm is summarized as:

Halve the image width and height, perhaps repeatedly, until the image conforms to the size constraints.

The following illustrates the process. Bear in mind that this optimization applies to each image in a workspace.

Bluescape Image Handling Example

Given a Bluescape workspace containing the three images depicted below:

  1. An image with 4000 x 2000-pixel resolution
  2. An image with 6000 x 3000-pixel resolution
  3. An image with 18000 x 4000-pixel resolution

The result is:

  1. No downscaling occurs as the width and height are within limits, and the total # of pixels (at 2000*4000 pixels = 8-megapixels) is within the 12-megapixel upper limit
  2. The image is downscaled as it is larger than 12 megapixels in resolution (6000*3000 pixels = 18 megapixels). Consequently, its width and height are halved, resulting in 3000 x 1500 resolution, which, at 4.5-megapixel resolution, is well within the 12- megapixel limit.
  3. Image 3 exceeds the total resolution and, at 18000 pixels in height, the 16384- pixel threshold. It is halved twice in order to fit within the constraints (18000 x 4000 → 9000 x 2000 → 4500 x 1000).

Now that individual images have been assessed and resized as required, the second phase of optimization occurs, where the aggregate of all resulting images receives assessment and possibly downscale to reduce memory consumption.

Optimizations Applied to All Images on a Wall Client

Extraordinarily complex workspaces may cause Bluescape to consume excessive amounts of memory. Accordingly, Bluescape limits to 3.2-gigapixels (3.2 billion pixels) the total pixels of all images in a workspace sent to a wall client. If you exceed this limit, Bluescape conserves memory by halving the resolution of all workspace images to ensure that the total pixel count in the workspace does not exceed 3.2-gigapixels. This calculation is applied after each image has received individual assessment and possibly downscaled as described above.

Example

A Workspace contains 500 images, each at 4,000 x 2,800 pixels. The total size of this workspace is 5.6 Billion pixels. This workspace exceeds the upper limit of 3.2- gigapixels of the Bluescape wall client. Therefore, the workspace will undergo a global image reduction. Each of the 500 images is at the new downscaled resolution of 2,000 x 1,400 pixels as they get sent to the Bluescape wall client. Original image resolution maintains in the workspace for the ability to download or view in a browser client.

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