agentSkill
Slack Gif Creator
Knowledge and utilities for creating animated GIFs optimized for Slack. Provides constraints, validation tools, and animation concepts. Use when users request animated GIFs for Slack like "make me a GIF of X doing Y for Slack."
| name | slack-gif-creator |
| description | Knowledge and utilities for creating animated GIFs optimized for Slack. Provides constraints, validation tools, and animation concepts. Use when users request animated GIFs for Slack like "make me a GIF of X doing Y for Slack." |
| license | Complete terms in LICENSE.txt |
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
pythonfrom 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:
pythonfrom 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:
pythonfrom 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 (
creategradientbackground)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:
pythonbuilder = 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:
pythonfrom 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:
pythonfrom 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:
pythonfrom 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()ormath.cos()with frame indexAdd small random variations for natural feel
Apply to x and/or y position
Pulse/Heartbeat
Scale object size rhythmically:
Use
math.sin(tfrequency2*math.pi)for smooth pulseFor 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()witheasing='bounce_out'for landingUse
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()witheasing='ease_out'for smooth stopFor 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 += vyAdd gravity:
vy += gravity_constantFade 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=48instead of 128Smaller dimensions - 128x128 instead of 480x480
Remove duplicates -
remove_duplicates=Truein save()Emoji mode -
optimizeforemoji=Trueauto-optimizes
python# 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
bashpip install pillow imageio numpy
