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Glossary

The glossary provides a short definition of the most common terms, and provides links to the related entries.

Check mode

The check mode sets how an element reacts to touch and raises the corresponding event.

Three modes are available: normal, instant and direct.

The state of the GUI element needs to be enabled.

Colours

The monochrome e-paper screens provides 2 basic colours: black and white.

Combining those 2 basic colours gives one additional shade, totalling 3 colours.

  • white: basic colour

  • black: basic colour

  • grey: combined colour, one dot black, another dot white

The colour e-paper screens provides 3 basic colours. Combining those 3 basic colours gives two additional shades, totalling 6 colours.

  • white: basic colour;

  • black: basic colour;

  • red: basic colour.

and

  • grey: combined colour, one pixel black, another pixel white;

  • light red: combined colour, one pixel red, another pixel white;

  • dark red: combined colour, one pixel red, another pixel black.

Coordinates

Two systems are available:

  • Rectangular coordinates define the top-left and bottom-right points;

  • Vector coordinates define the top-left point and a distance.

Delegated update

Normally, the main code commands the refresh of the screen.

With the delegated update option, the elements can trigger the refresh of the screen, with the partial update mode. This allows a more fluid interface, especially for the GUI library.

Direct check

Default mode is normal check mode.

In direct check mode, the GUI element raises the event when the finger is released from the element. A simplified cinematic sequence is performed.

The mode is recommended when the button triggers the display of a new page.

It requires the state of the GUI element to be enabled.

Disabled state

A GUI element with a disabled state does not react to touch.

See also

Enabled state, State

Element

An element is a basic interface component, either a self-contained high-level function or a object.

The GUI elements react to touch, with two parameters: state, enabled or disabled; and mode, normal or instant.

See also

Check mode, State

Enabled state

A GUI element with an enabled state reacts to touch and raises the corresponding event.

See also

State, Disabled state

Fast update

The fast update is faster than the global update mode. First, the previous and next contents of the full screen are uploaded to the screen, and then the screen refreshes without the blinking effect.

It supports monochrome screens only, and possible ghosting may appear.

The fast update offers a good balance between quality and speed.

File formats

There are multiple options to store and retrieve the content of the screen:

  • Image structure;
  • Portable pixmap (with PBM or P4 extension);
  • Windows bitmap (with BMP extension).

Global update

The global update is the default for refreshing the screen. First, the next content of the full screen is uploaded to the screen, and then the screen refreshes with a blinking effect.

It supports both monochrome and colours screens. However, it is slower than the other modes.

The global update is recommended for optimal quality without any ghosting.

Image structure

The image structure is a specific file format to store the content of the screen.

It is used to write to a micro-SD card or to print to a serial console, for later reuse as a header file.

Instant check

Default mode is normal check mode.

In instant check mode, the GUI element raises the event when the finger touches the element. No cinematic sequence is performed.

It requires the state of the GUI element to be enabled.

Logical screen

The library deals with the logical screen, which takes into account the orientation, with x-y coordinates.

The coordinates for the logical screen are defined by the orientation.

Normal check

Default mode is normal check mode.

In normal check mode, the GUI element raises the event when the finger is released from the element. Additionally, the element goes through a cinematic sequence.

It requires the state of the GUI element to be enabled.

Page

A page is a set of elements that defines a screen of a human machine interface.

An application can have one single page or multiple pages.

See also

Element

Partial update

The partial update is the fastest among other update options. Instead of the full screen, only the previous and next contents of the modified window are uploaded to the screen, and then the screen refreshes without the blinking effect.

It supports monochrome screens only. Possible ghosting may appear, especially outside the modified window.

The partial update is highly recommended for human-machine interfaces.

Physical screen

The physical screen refers to the panel as described in the data-sheet, with horizontal-vertical coordinates.

The coordinates for the physical screen are consistent with the horizontal and vertical axes from the data-sheet.

The library manages the physical screen and exposes the logical screen to the application.

Portable pixmap

The portable pixmap is a compact file format with a PBM or P4 extension to store the content of the screen.

It is used to write to and read from a micro-SD card.

It is also available to print as a table to a serial console, for later reuse as a header file.

Rectangular coordinates

The rectangle coordinates include two points P1 and P2.

  • P1 is a pixel on the top left, with (x1, y1) coordinates.

  • P2 is a pixel on the bottom right, with (x2, y2) coordinates.

Example

rectangle (0, 0) - (319, 239)

Screen

A same screen is described as

  • a physical screen is the panel described in the data-sheet;

  • a logical screen is managed by the library and takes the orientation into account.

State

The state of a GUI element defines whether the element reacts to touch.

Two states are available:

  • if state is disabled, the element does not react to touch;

  • if state is enabled, the element reacts to touch and raises the corresponding event.

Update

Three modes are available for the update of the screen: global update, fast update, partial update.

Changing the content of the screen consists on three phases:

  1. initialising the panel;
  2. uploading the content of the frame-buffer to the panel; and
  3. refreshing the panel.
Update type Global Update Fast Update Partial Update
Supported panels Three-colours (BWR) and monochrome (B&W) panels Monochrome (B&W) panels Monochrome (B&W) panels
Initialisation Panel initialisation Panel initialisation Panel initialisation
Content upload Full screen with new content Full screen with previous and new contents Partial window with previous and new contents
Panel refresh Whole screen with flashing effect Whole screen with fast mode Partial window with fast mode
Image quality Optimal quality Possible ghosting Possible ghosting
Upload speed Slow Slow Fast
Refresh panel speed Slow Fast Fast
Overall speed Slow Faster Fastest

Vector coordinates

The vector coordinates include one point P0 and one distance.

  • P0 is a pixel and the origin, with (x0, y0) coordinates.

  • The distance (dx, dy) is specified on the x-y axes.

Example

vector (0, 0) - (320, 240)

Going from pixel 0 to pixel 319 represents 320 pixels in total.

Window

The window is the area to be updated on partial mode.

The library calculates the window automatically.

See also

Partial update

Windows bitmap

The Windows bitmap is a file format with a BMP extension to store the content of the screen.

It is used to write to and read from a micro-SD card.