doodles | Web Experiments I do for fun | Canvas library
kandi X-RAY | doodles Summary
kandi X-RAY | doodles Summary
To see the experiments, check out the homepage.
Support
Quality
Security
License
Reuse
Top functions reviewed by kandi - BETA
Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of doodles
doodles Key Features
doodles Examples and Code Snippets
Community Discussions
Trending Discussions on doodles
QUESTION
I am using a 3.5: TFT LCD display with an Arduino Uno and the library from the manufacturer, the KeDei TFT library. The library came with a bitmap font table that is huge for the small amount of memory of an Arduino Uno so I've been looking for alternatives.
What I am running into is that there doesn't seem to be a standard representation and some of the bitmap font tables I've found work fine and others display as strange doodles and marks or they display upside down or they display with letters flipped. After writing a simple application to display some of the characters, I finally realized that different bitmaps use different character orientations.
My questionWhat are the rules or standards or expected representations for the bit data for bitmap fonts? Why do there seem to be several different text character orientations used with bitmap fonts?
Thoughts about the questionAre these due to different target devices such as a Windows display driver or a Linux display driver versus a bare metal Arduino TFT LCD display driver?
What is the criteria used to determine a particular bitmap font representation as a series of unsigned char values? Are different types of raster devices such as a TFT LCD display and its controller have a different sequence of bits when drawing on the display surface by setting pixel colors?
What other possible bitmap font representations requiring a transformation which my version of the library currently doesn't offer, are there?
Is there some method other than the approach I'm using to determine what transformation is needed? I currently plug the bitmap font table into a test program and print out a set of characters to see how it looks and then fine tune the transformation by testing with the Arduino and the TFT LCD screen.
My experience thus farThe KeDei TFT library came with an a bitmap font table that was defined as
...ANSWER
Answered 2021-Jun-12 at 16:19Raster 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:
QUESTION
I'm displaying an image using FutureBuilder
.
I tried using https://stackoverflow.com/a/52021385/7068790. But the image still not show.
ANSWER
Answered 2021-May-01 at 19:32Your getImage method doesn't do anything. It lacks a return statement and thus _imageUrl won't ever return a String and only return null.
If you see Future
in your code you should ask yourself why you are using the ?
. If you would actually get a String Flutter wouldn't tell you to use Future
but you could write Future
. That's the great thing about Flutter's new null-safety futures, it complains in a case like this if you are returning null.
So to fix your code you need to do:
QUESTION
I am trying to initialize a set with a bunch of data. But when I check some items that are already inserted with the contains function, it returns false.
What is wrong with this code?
...ANSWER
Answered 2021-Feb-21 at 04:52you initialize with name "set" but doing addAll for "proSet"? I don't see anything wrong beside it. but, for better reading options, it could be:
QUESTION
I send data with ajax using the POST method.
Once the data are sent $_POST['my_value'] remains empty.
However the expected value is in $_GET['my_value'].
Here is my ajax call:
...ANSWER
Answered 2021-Feb-04 at 16:43The PHP superglobals $_POST
and $_GET
are not directly related to the HTTP request method.
$_GET
is populated with data from the URL's query string.
$_POST
is populated with data from the request body (if it uses a supported encoding like application/www-url-encoded
).
We can't see what URL you are passing, but since you say the data is showing up in $_GET
you must have put the data there.
We can see what you put in the request body — null
— so the body will be empty.
If you want to populate the body you could do something like:
QUESTION
I am looking for the best way to position an image so that it hangs into the screen exactly at the image's halfway point.
I have looked around and found various things about positioning within a div, but not within the entire screen.
I have tried position: absolute;
, background-position
and other css styles.
Using percentages does not work properly as when the screen is resized, the image moves left/right and is not fixed on its vertical axis.
...ANSWER
Answered 2020-Dec-11 at 21:58Common Solution
margin: 0 auto;
is the most common and simple solution for centering a div
in the screen or its parent. margin: 0 auto;
is shorthand to set the top and bottom margins to zero and the left and right margins to auto.
QUESTION
I'm trying to parse this JSON CSP Record being submitted via POST
directly by the browser into a nested struct:
ANSWER
Answered 2020-Oct-01 at 06:59JSON from rocket_contrib is a convenience, but not essential. You can still parse the JSON yourself from the raw body data with serde (following example is done with async Rocket). This may bypass any issues with headers:
QUESTION
I have html that looks like this:
...ANSWER
Answered 2020-Sep-23 at 21:29You can use for this innerHTML
property.
Example:
QUESTION
I created a Leaflet Map with a Legend. The goal would be to hover over the text element in the legend area and show a tooltip with a image.
Problem: hover is not showing up! I tried very different version. The easiest way which should usually work is this one:
...ANSWER
Answered 2020-Sep-16 at 15:57You have to use JQuery UI to get access to tooltip. https://jqueryui.com/
Here is your code after editing in jsfiddle. http://jsfiddle.net/2qrbzstu/
QUESTION
I have a struct
...ANSWER
Answered 2020-May-15 at 19:20Seeing as the only difference between the two functions is which property you read from, you could add a boolean argument to your function that determines whether you're reading from the x
or y
property.
QUESTION
Is there a way to make each image (that has a certain class) clickable?
I want jQuery to:
- Read the
src
of the image. - Wrap the image with an
a href
that contains that src url.
ANSWER
Answered 2020-Apr-29 at 18:12I hope you want something like this:
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install doodles
Support
Reuse Trending Solutions
Find, review, and download reusable Libraries, Code Snippets, Cloud APIs from over 650 million Knowledge Items
Find more librariesStay Updated
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page