DEV Community: Comficker

HTML Canvas cheat sheet

Comficker — Fri, 06 Oct 2023 03:26:44 +0000

Certainly! Here's an HTML Canvas cheat sheet that covers some of the commonly used methods and properties:

Canvas Setup:

<!-- Create a canvas element -->
<canvas id="myCanvas"></canvas>

<!-- Get the canvas element in JavaScript -->
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");

Drawing Shapes:

// Draw a rectangle
ctx.beginPath();
ctx.rect(x, y, width, height);
ctx.fillStyle = "color";
ctx.fill();
ctx.closePath();

// Draw a circle
ctx.beginPath();
ctx.arc(x, y, radius, startAngle, endAngle, anticlockwise);
ctx.fillStyle = "color";
ctx.fill();
ctx.closePath();

// Draw a line
ctx.beginPath();
ctx.moveTo(x1, y1);
ctx.lineTo(x2, y2);
ctx.strokeStyle = "color";
ctx.stroke();
ctx.closePath();

Text Manipulation:

ctx.font = "fontStyle fontSize fontFamily";
ctx.fillStyle = "color";
ctx.fillText("Text", x, y);
ctx.strokeText("Text", x, y);

Colors and Styles:

// Set fill color
ctx.fillStyle = "color";

// Set stroke color
ctx.strokeStyle = "color";

// Set line width
ctx.lineWidth = width;

// Set line join style
ctx.lineJoin = "style";

// Set line cap style
ctx.lineCap = "style";

// Set shadow
ctx.shadowColor = "color";
ctx.shadowBlur = value;
ctx.shadowOffsetX = value;
ctx.shadowOffsetY = value;

Transformations:

// Translate the canvas origin
ctx.translate(x, y);

// Scale the canvas
ctx.scale(scaleX, scaleY);

// Rotate the canvas
ctx.rotate(angle);

// Reset transformations
ctx.setTransform(1, 0, 0, 1, 0, 0);

Image Manipulation:

// Draw an image
var img = new Image();
img.src = "imageURL";
img.onload = function() {
    ctx.drawImage(img, x, y, width, height);
}

// Draw a portion of an image
ctx.drawImage(img, sx, sy, sWidth, sHeight, dx, dy, dWidth, dHeight);

// Create a pattern with an image
var pattern = ctx.createPattern(image, "repeat/repeat-x/repeat-y/no-repeat");
ctx.fillStyle = pattern;
ctx.fill();

Demo using html canvas: Pixel Art Editor

Working with Django Models

Comficker — Wed, 19 Oct 2022 02:42:03 +0000

Defining a model

To define the models for your app, modify the file models.py that was created in your app’s folder. The str() method tells Django how to represent data objects based on this model.

from django.db import models
"""A topic the user is learning about."""
class Topic(models.Model):
    text = models.CharField(max_length=200)
    date_added = models.DateTimeField(
    auto_now_add=True)

    def str(self):
         return self.text

Defining a model with a foreign key

class Entry(models.Model):
    """Learning log entries for a topic."""
    topic = models.ForeignKey(Topic)
    text = models.TextField()
    date_added = models.DateTimeField(
    auto_now_add=True)
    def str(self):
        return self.text[:50] + "…"

Activating a model

To use a model the app must be added to the tuple INSTALLED_APPS, which is stored in the project’s settings.py file

INSTALLED_APPS = (
    --snip--
    'django.contrib.staticfiles',
    # My apps
    'learning_logs',
)

Migrating the database

The database needs to be modified to store the kind of data that the model represents.

python manage.py makemigrations learning_logs
python manage.py migrate

Creating a superuser

A superuser is a user account that has access to all aspects of the project.

python manage.py createsuperuser

Registering a model

You can register your models with Django’s admin site, which
makes it easier to work with the data in your project. To do this, modify the app’s admin.py file.

from django.contrib import admin
from learning_logs.models import Topic
admin.site.register(Topic)

Django Cheat Sheet

Install Django

Comficker — Wed, 19 Oct 2022 02:39:12 +0000

It’s usually best to install Django to a virtual environment, where your project can be isolated from your other Python projects. Most commands assume you’re working in an active virtual environment.

Create a virtual environment

$ python –m venv v

Activate the environment (Linux and OS X)

$ source v/bin/activate

Activate the environment (Windows)

venv\Scripts\activate

Install Django to the active environment

(venv)$ pip install Django

Django Cheat Sheet

Managing Conda and Anaconda

Comficker — Tue, 18 Oct 2022 15:56:29 +0000

Verify conda is installed, check version #

conda info

Update conda package and environment manager

conda update conda

Update the anaconda meta package

conda update anaconda

JAVA SWING Cheat Sheet: JLabel Class

Comficker — Thu, 06 Oct 2022 14:03:14 +0000

Following is the declaration for javax.swing.JLabel class −
Following are the fields for javax.swing.JLabel class

protected Component labelFor

JLabel() - Creates a JLabel instance with no image and with an empty string for the title.
JLabel(Icon image) - Creates a JLabel instance with the specified image.
JLabel(Icon image, int horizontalAlignment) - Creates a JLabel instance with the specified image and horizontal alignment.
JLabel(String text) - Creates a JLabel instance with the specified text.
JLabel(String text, Icon icon, int horizontalAlignment) - Creates a JLabel instance with the specified text, image, and horizontal alignment.
JLabel(String text, int horizontalAlignment) - Creates a JLabel instance with the specified text and horizontal alignment.

Swing Cheat Sheet

Is heroku down right now?

Comficker — Mon, 03 Oct 2022 07:00:24 +0000