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CSS and Scratch Jr.

Pinball Game Comparison: Scratch Jr vs CSS3 with SVG Animation

| Feature | Scratch Jr Pinball | CSS3 Pinball (SVG Animation Only) | |----------------------------|--------------------------------------------------|----------------------------------------------------| | Platform | Tablet app with visual blocks | Web browser using HTML + CSS3 + SVG | | Programming Model | Block-based, event-driven | Declarative SVG markup with embedded animation | | Ball Movement | Manual motion blocks (looped) | <animateMotion> along <path> with timing curves | | Collision Detection | Touching sprite triggers | Simulated via timed motion and SVG <animate> resets | | Flipper Mechanics | Tap-triggered sprite motion | <animateTransform> triggered by CSS :hover or :active | | Scoring System | Visual only (no variables) | Limited; symbolic scoring via visual state changes | | Input Handling | Tap on sprites | Limited to hover, focus, or checkbox toggles | | Physics Simulation | None (manual direction changes) | None; bounce simulated via path redirection | | Game Loop | Looped motion blocks | Infinite SVG animation cycles | | Graphics | Cartoon sprites | Vector shapes, gradients, and styled SVG elements | | Sound Effects | Limited preset sounds | Not possible with SVG/CSS alone | | Educational Focus | Early logic and sequencing | Creative use of declarative animation and geometry | | Complexity Ceiling | Low (no variables or math) | Medium (requires SVG path logic and timing control) |

Algebra of CSS

How Algebra Can Help with CSS

Algebra can play a crucial role in CSS (Cascading Style Sheets) by helping you create more dynamic, flexible, and responsive designs. Here are some ways algebra can be applied to CSS:

Calculations for Layout

.container {
  width: 80%; /* Calculate 80% of the parent element
}

.grid-item { width: calc(100% / 12 * 3); /* Spans 3 out of 12 columns */ }

@media (max-width: 768px) { .responsive-element { font-size: calc(16px + 0.5vw); /* Adjusts size based on viewport width */ } } 

.centered-element { position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); /* Centers the element */ }

.dynamic-spacing { margin-top: calc(10px + 2%); /* Combines fixed and relative units */ } 

.animated-element { animation: move 2s ease-in-out; } @keyframes move { 0% { left: 0; } 50% { left: calc(100% - 50px); } 100% { left: 0; } }

Dynamic CSS

To add a background-image rule via the CSSOM, first get a reference to the rules of the first stylesheet:

var stylesheet = document.styleSheets[0].cssRules;

Then, get a reference to the end of the stylesheet:

var end = stylesheet.length - 1;

Finally, insert a background-image rule for the body element at the end of the stylesheet:

stylesheet.insertRule("body { background-image: url('http://cdn.sstatic.net/Sites/stackoverflow/img/favicon.ico'); }", end);

CSS Postprocessing

Use a callback function to add/remove styles via postprocessing, for example with Vite.js to add/remove tailwind style rules:

import { defineConfig } from 'vite';
import postcssImport from 'postcss-import';
import tailwindcss from 'tailwindcss';
import autoprefixer from 'autoprefixer';

export default defineConfig(({ mode }) => {
  const isProduction = mode === 'production';

  return {
    css: {
      postcss: {
        plugins: [
          postcssImport(),
          isProduction ? tailwindcss() : {
            postcssPlugin: 'tailwind-skipping-plugin',
            Once(root, { result }) {
              root.walkRules(rule => {
                if (rule.selector.includes('tw-')) {
                  rule.remove();
                }
              });
            },
          },
          autoprefixer(),
        ].filter(Boolean),
      },
    },
  };
});

Animation

Set Theory

Real-Time Editing

Adaptive Design

Postprocessing

Videos

References

Games

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