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 from core . gif_builder import GIFBuilder from PIL import Image , ImageDraw

1. Create builder

builder

GIFBuilder ( width = 128 , height = 128 , fps = 10 )

2. Generate frames

for i in range ( 12 ) : frame = Image . new ( 'RGB' , ( 128 , 128 ) , ( 240 , 248 , 255 ) ) draw = ImageDraw . Draw ( frame )

Draw your animation using PIL primitives

(circles, polygons, lines, etc.)

builder . add_frame ( frame )

3. Save with optimization

builder . save ( 'output.gif' , num_colors = 48 , optimize_for_emoji = True ) 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: from PIL import Image uploaded = Image . open ( 'file.png' )

Use directly, or just as reference for colors/style

Drawing from Scratch When drawing graphics from scratch, use PIL ImageDraw primitives: from PIL import ImageDraw draw = ImageDraw . Draw ( frame )

Circles/ovals

draw . ellipse ( [ x1 , y1 , x2 , y2 ] , fill = ( r , g , b ) , outline = ( r , g , b ) , width = 3 )

Stars, triangles, any polygon

points

[ ( x1 , y1 ) , ( x2 , y2 ) , ( x3 , y3 ) , . . . ] draw . polygon ( points , fill = ( r , g , b ) , outline = ( r , g , b ) , width = 3 )

Lines

draw . line ( [ ( x1 , y1 ) , ( x2 , y2 ) ] , fill = ( r , g , b ) , width = 5 )

Rectangles

draw . rectangle ( [ x1 , y1 , x2 , y2 ] , fill = ( r , g , b ) , outline = ( r , g , b ) , width = 3 ) 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: builder = GIFBuilder ( width = 128 , height = 128 , fps = 10 ) builder . add_frame ( frame )

Add PIL Image

builder . add_frames ( frames )

Add list of frames

builder . save ( 'out.gif' , num_colors = 48 , optimize_for_emoji = True , remove_duplicates = True ) Validators ( core.validators ) Check if GIF meets Slack requirements: from core . validators import validate_gif , is_slack_ready

Detailed validation

passes , info = validate_gif ( 'my.gif' , is_emoji = True , verbose = True )

Quick check

if is_slack_ready ( 'my.gif' ) : print ( "Ready!" ) Easing Functions ( core.easing ) Smooth motion instead of linear: from core . easing import interpolate

Progress from 0.0 to 1.0

t

i / ( num_frames - 1 )

Apply easing

y

interpolate ( start = 0 , end = 400 , t = t , easing = 'ease_out' )

Available: linear, ease_in, ease_out, ease_in_out,

bounce_out, elastic_out, back_out

Frame Helpers ( core.frame_composer ) Convenience functions for common needs: from core . frame_composer import ( create_blank_frame ,

Solid color background

create_gradient_background ,

Vertical gradient

draw_circle ,

Helper for circles

draw_text ,

Simple text rendering

draw_star

5-pointed star

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

Maximum optimization for emoji

builder

.

save

(

'emoji.gif'

,

num_colors

=

48

,

optimize_for_emoji

=

True

,

remove_duplicates

=

True

)

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 pip install pillow imageio numpy