experiments | random bits , snippets | GPU library

Raster or bitmap fonts are represented in a number of different ways and there are bitmap font file standards that have been developed for both Linux and Windows. However raw data representation of bitmap fonts in programming language source code seems to vary depending on:

• the memory architecture of the target computer,
• the architecture and communication pathways to the display controller,
• character glyph height and width in pixels and
• the amount of memory for bitmap storage and what measures are taken to make that as small as possible.

A brief overview of bitmap fonts

A generic bitmap is a block of data in which individual bits are used to indicate a state of either on or off. One use of a bitmap is to store image data. Character glyphs can be created and stored as a collection of images, one for each character in the character set, so using a bitmap to encode and store each character image is a natural fit.

Bitmap fonts are bitmaps used to indicate how to display or print characters by turning on or off pixels or printing or not printing dots on a page. See Wikipedia Bitmap fonts

A bitmap font is one that stores each glyph as an array of pixels (that is, a bitmap). It is less commonly known as a raster font or a pixel font. Bitmap fonts are simply collections of raster images of glyphs. For each variant of the font, there is a complete set of glyph images, with each set containing an image for each character. For example, if a font has three sizes, and any combination of bold and italic, then there must be 12 complete sets of images.

A brief history of using bitmap fonts

The earliest user interface terminals such as teletype terminals used dot matrix printer mechanisms to print on rolls of paper. With the development of Cathode Ray Tube terminals bitmap fonts were readily transferable to that technology as dots of luminescence turned on and off by a scanning electron gun.

Earliest bitmap fonts were of a fixed height and width with the bitmap acting as a kind of stamp or pattern to print characters on the output medium, paper or display tube, with a fixed line height and a fixed line width such as the 80 columns and 24 lines of the DEC VT-100 terminal.

With increasing processing power, a more sophisticated typographical approach became available with vector fonts used to improve displayed text quality and provide improved scaling while also reducing memory required to describe the character glyphs.

In addition, while a matrix of dots or pixels worked fairly well for languages such as English, written languages with complex glyph forms were poorly served by bitmap fonts.

Representation of bitmap fonts in source code

There are a number of bitmap font file formats which provide a way to represent a bitmap font in a device independent description. For an example see Wikipedia topic - Glyph Bitmap Distribution Format

The Glyph Bitmap Distribution Format (BDF) by Adobe is a file format for storing bitmap fonts. The content takes the form of a text file intended to be human- and computer-readable. BDF is typically used in Unix X Window environments. It has largely been replaced by the PCF font format which is somewhat more efficient, and by scalable fonts such as OpenType and TrueType fonts.

Other bitmap standards such as XBM, Wikipedia topic - X BitMap, or XPM, Wikipedia topic - X PixMap, are source code components that describe bitmaps however many of these are not meant for bitmap fonts specifically but rather other graphical images such as icons, cursors, etc.

As bitmap fonts are an older format many times bitmap fonts are wrapped within another font standard such as TrueType in order to be compatible with the standard font subsystems of modern operating systems such as Linux and Windows.

However embedded systems that are running on the bare metal or using an RTOS will normally need the raw bitmap character image data in the form similar to the XBM format. See Encyclopedia of Graphics File Formats which has this example:

Following is an example of a 16x16 bitmap stored using both its X10 and X11 variations. Note that each array contains exactly the same data, but is stored using different data word types:

As I understand, for code

You could use recast from reshape2 package:

This will copy the input file to the project build/ directory and replace the token in the copy:

Totally been in your shoes before. This code sample seems a smidge out of date. Using this notebook as a reference, can you try the following?

I guess you are trying to use firebase as a signalling medium and want to use react-native-webrtc for the video calling.

Here is the sample code I have for the same solution with the latest libraries and react-native version.

Firebase Installation React Native.

Just set up ios and android using this above link and then use the below code for reference.

The system channel is used by the ordering service as a template to create application channels. The nodes of the ordering service that are defined in the system channel become the default consenter set of new channels, while the administrators of the ordering service become the orderer administrators of the channel.

so you define Orderer at Profile application channel section is useless

but the ordering nodes can be added or removed from the channel by updating the application channel configuration

so if you want to use seperate orderers per channel,after create application channel ,remove the consenter set of your application channel config you can reference https://hyperledger-fabric.readthedocs.io/en/release-2.2/config_update.html

https://kctheservant.medium.com/add-an-orderer-to-a-running-raft-based-orderer-cluster-b6a432da138c

I have use seperate orderers per channel successful at version 1.4.2,I think it is easier for version 2.3.x. because you can setup your fabric network without system channel.

If the goal is to get a marker's popup to open, on the condition that the marker's id is specified in the url param (i.e. url?id=3), this is doable.

You'll want to map over an array of markers, each with a unique id. You'll need to keep an array or object of refs, and as you map, in the ref prop, add the ref to that array of object: