Slack GIF Creator

A toolkit providing utilities and knowledge for creating animated GIFs optimized for Slack.

Slack Requirements

Dimensions:

• Emoji GIFs: 128x128 (recommended)
• Message GIFs: 480x480

Parameters:

• FPS: 10-30 (lower is smaller file size)
• Colors: 48-128 (fewer = smaller file size)
• Duration: Keep under 3 seconds for emoji GIFs

Core Workflow

Drawing Graphics

Working with User-Uploaded Images

If a user uploads an image, consider whether they want to:

• Use it directly (e.g., "animate this", "split this into frames")
• Use it as inspiration (e.g., "make something like this")

Load and work with images using PIL:

Drawing from Scratch

When drawing graphics from scratch, use PIL ImageDraw primitives:

Don't use: Emoji fonts (unreliable across platforms) or assume pre-packaged graphics exist in this skill.

Making Graphics Look Good

Graphics should look polished and creative, not basic. Here's how:

Use thicker lines - Always set width=2 or higher for outlines and lines. Thin lines (width=1) look choppy and amateurish.

Add visual depth:

• Use gradients for backgrounds (create_gradient_background)
• Layer multiple shapes for complexity (e.g., a star with a smaller star inside)

Make shapes more interesting:

• Don't just draw a plain circle - add highlights, rings, or patterns
• Stars can have glows (draw larger, semi-transparent versions behind)
• Combine multiple shapes (stars + sparkles, circles + rings)

Pay attention to colors:

• Use vibrant, complementary colors
• Add contrast (dark outlines on light shapes, light outlines on dark shapes)
• Consider the overall composition

For complex shapes (hearts, snowflakes, etc.):

• Use combinations of polygons and ellipses
• Calculate points carefully for symmetry
• Add details (a heart can have a highlight curve, snowflakes have intricate branches)

Be creative and detailed! A good Slack GIF should look polished, not like placeholder graphics.

Available Utilities

GIFBuilder (core.gif_builder)

Assembles frames and optimizes for Slack:

Validators (core.validators)

Check if GIF meets Slack requirements:

Easing Functions (core.easing)

Smooth motion instead of linear:

Frame Helpers (core.frame_composer)

Convenience functions for common needs:

Animation Concepts

Shake/Vibrate

Offset object position with oscillation:

• Use math.sin() or math.cos() with frame index
• Add small random variations for natural feel
• Apply to x and/or y position

Pulse/Heartbeat

Scale object size rhythmically:

• Use math.sin(t * frequency * 2 * math.pi) for smooth pulse
• For heartbeat: two quick pulses then pause (adjust sine wave)
• Scale between 0.8 and 1.2 of base size

Bounce

Object falls and bounces:

• Use interpolate() with easing='bounce_out' for landing
• Use easing='ease_in' for falling (accelerating)
• Apply gravity by increasing y velocity each frame

Spin/Rotate

Rotate object around center:

• PIL: image.rotate(angle, resample=Image.BICUBIC)
• For wobble: use sine wave for angle instead of linear

Fade In/Out

Gradually appear or disappear:

• Create RGBA image, adjust alpha channel
• Or use Image.blend(image1, image2, alpha)
• Fade in: alpha from 0 to 1
• Fade out: alpha from 1 to 0

Slide

Move object from off-screen to position:

• Start position: outside frame bounds
• End position: target location
• Use interpolate() with easing='ease_out' for smooth stop
• For overshoot: use easing='back_out'

Zoom

Scale and position for zoom effect:

• Zoom in: scale from 0.1 to 2.0, crop center
• Zoom out: scale from 2.0 to 1.0
• Can add motion blur for drama (PIL filter)

Explode/Particle Burst

Create particles radiating outward:

• Generate particles with random angles and velocities
• Update each particle: x += vx, y += vy
• Add gravity: vy += gravity_constant
• Fade out particles over time (reduce alpha)

Optimization Strategies

Only when asked to make the file size smaller, implement a few of the following methods:

1. Fewer frames - Lower FPS (10 instead of 20) or shorter duration
2. Fewer colors - num_colors=48 instead of 128
3. Smaller dimensions - 128x128 instead of 480x480
4. Remove duplicates - remove_duplicates=True in save()
5. Emoji mode - optimize_for_emoji=True auto-optimizes

Philosophy

This skill provides:

• Knowledge: Slack's requirements and animation concepts
• Utilities: GIFBuilder, validators, easing functions
• Flexibility: Create the animation logic using PIL primitives

It does NOT provide:

• Rigid animation templates or pre-made functions
• Emoji font rendering (unreliable across platforms)
• A library of pre-packaged graphics built into the skill

Note on user uploads: This skill doesn't include pre-built graphics, but if a user uploads an image, use PIL to load and work with it - interpret based on their request whether they want it used directly or just as inspiration.

Be creative! Combine concepts (bouncing + rotating, pulsing + sliding, etc.) and use PIL's full capabilities.

Dependencies