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Overview

DevCPC can automatically convert PNG images to Amstrad CPC formats during the build process:
  • Sprites: PNG → ASM data files for use in your game
  • Screens: PNG → SCN binary files for loading screens
Requires Python Pillow library: pip3 install Pillow

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CPC Video Modes

The MODE setting determines the video mode for all graphics conversions.

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MODE=0: 16 Colors

devcpc.conf
MODE=0
  • Resolution: 160×200 pixels
  • Colors: 16 simultaneous colors (from 27-color palette)
  • Encoding: 2 pixels per byte (4 bits per pixel)
  • Best for: Colorful games, detailed sprites, most projects
PNG Requirements:
  • Width: Multiple of 2 pixels
  • Height: Any
  • Colors: Maximum 16 colors
  • For screens: Exactly 160×200 pixels

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MODE=1: 4 Colors

devcpc.conf
MODE=1
  • Resolution: 320×200 pixels
  • Colors: 4 simultaneous colors (from 27-color palette)
  • Encoding: 4 pixels per byte (2 bits per pixel)
  • Best for: Higher resolution games, text-heavy interfaces
PNG Requirements:
  • Width: Multiple of 4 pixels
  • Height: Any
  • Colors: Maximum 4 colors
  • For screens: Exactly 320×200 pixels

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MODE=2: 2 Colors

devcpc.conf
MODE=2
  • Resolution: 640×200 pixels
  • Colors: 2 colors (typically black and white)
  • Encoding: 8 pixels per byte (1 bit per pixel)
  • Best for: Hi-res monochrome graphics, arcade ports
PNG Requirements:
  • Width: Multiple of 8 pixels
  • Height: Any
  • Colors: Maximum 2 colors
  • For screens: Exactly 640×200 pixels

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CPC Color Palette

The Amstrad CPC has a fixed 27-color palette (INK 0-26). DevCPC automatically converts PNG RGB colors to the nearest CPC ink.

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Hardware Palette

INKColorRGBHex
0Black(0,0,0)#000000
1Blue (dark)(0,0,128)#000080
2Blue(0,0,255)#0000FF
3Red (dark)(128,0,0)#800000
4Magenta (dark)(128,0,128)#800080
5Magenta(128,0,255)#8000FF
6Red(255,0,0)#FF0000
7Pink(255,0,128)#FF0080
8Pink (light)(255,0,255)#FF00FF
9Green (dark)(0,128,0)#008000
10Cyan (dark)(0,128,128)#008080
11Cyan(0,128,255)#0080FF
12Yellow (dark)(128,128,0)#808000
13Gray(128,128,128)#808080
14Blue (pastel)(128,128,255)#8080FF
15Orange(255,128,0)#FF8000
16Pink (pastel)(255,128,128)#FF8080
17Lilac(255,128,255)#FF80FF
18Green(0,255,0)#00FF00
19Aqua(0,255,128)#00FF80
20Cyan (light)(0,255,255)#00FFFF
21Yellow-green(128,255,0)#80FF00
22Green (pastel)(128,255,128)#80FF80
23Cyan (pastel)(128,255,255)#80FFFF
24Yellow(255,255,0)#FFFF00
25Yellow (pastel)(255,255,128)#FFFF80
26White(255,255,255)#FFFFFF
Use these exact RGB values in your PNG for perfect color matching, or use SPRITES_TOLERANCE to allow close matches.

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Sprite Configuration

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SPRITES_PATH

Directory containing PNG sprite files.
devcpc.conf
SPRITES_PATH="assets/sprites"
  • Type: Directory path
  • Search: Recursive (includes all subdirectories)
  • Process: Converts all PNG files to ASM format
  • Timing: Runs before ASM compilation during devcpc build

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SPRITES_OUT_FILE

Output file for generated sprite data.
devcpc.conf
SPRITES_OUT_FILE="ASM/sprites.asm"
  • Type: File path
  • Default: "sprites.asm" (in project root)
  • Format: ASM file with sprite data and palette information
  • Usage: Include in your ASM with include "sprites.asm"
Generated ASM structure: 
; MODE 0

PLAYER
;------ BEGIN IMAGE --------
  db 2          ; width in bytes
  db 16         ; height in pixels
  db 0, 0       ; sprite data
  db 85, 85
  ; ... more bytes ...
;------ END IMAGE --------
  ; Palette (PEN -> INK) detected in PNG
  ; INK 0,0
  ; INK 1,24
  ; INK 2,6

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SPRITES_TOLERANCE

RGB color matching tolerance.
devcpc.conf
SPRITES_TOLERANCE=8
  • Type: Integer
  • Values:
    • 0 = Exact match (RGB must exactly match CPC palette)
    • 1-255 = Tolerance in RGB delta (8 is recommended)
    • -1 = Automatic (always finds closest color)
  • Default: 8
  • Recommendation: Use 8 for most projects
How tolerance works: 
PNG color: RGB(250, 248, 0)
CPC INK 24: RGB(255, 255, 0)

Delta: sqrt((250-255)² + (248-255)² + (0-0)²) = 8.6

TOLERANCE=0:  ✗ Too different, error
TOLERANCE=8:  ✗ Exceeds tolerance, error
TOLERANCE=9:  ✓ Within tolerance, uses INK 24
TOLERANCE=-1: ✓ Uses closest match (INK 24)

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SPRITES_TRANSPARENT_INK

INK to use for transparent pixels.
devcpc.conf
SPRITES_TRANSPARENT_INK=""
  • Type: Integer (0-26) or empty
  • Default: Empty (no special transparency handling)
  • Usage: Maps PNG alpha=0 pixels to specified INK
  • Example: SPRITES_TRANSPARENT_INK=0 treats transparent pixels as black
Leave empty for no transparency, or set to your background INK color.

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Screen Configuration

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LOADER_SCREEN

Directory containing PNG loading screen files.
devcpc.conf
LOADER_SCREEN="assets/screen"
  • Type: Directory path
  • Search: Recursive (includes all subdirectories)
  • Process: Converts PNG to SCN format (16KB binary screen dump)
  • Address: SCN files load at &C000 (video memory)
  • Timing: Runs before ASM compilation during devcpc build
Output files:
  • obj/filename.scn - Binary screen dump (16384 bytes)
  • obj/filename.scn.info - Palette and format information

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Sprite Conversion Examples

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Example 1: Simple Sprites

Configuration:
devcpc.conf
MODE=0
SPRITES_PATH="assets/sprites"
SPRITES_OUT_FILE="ASM/sprites.asm"
SPRITES_TOLERANCE=8
Directory structure: 
assets/sprites/
├── player.png      (16×16, 4 colors)
├── enemy1.png      (16×16, 3 colors)
└── bullet.png      (4×8, 2 colors)
Build output: 
✓ Sprites convertidos exitosamente

Resumen:
PNG           Label      Size(px)  Bytes/line  Colors  Status
player.png    PLAYER     16x16     2           4       OK
enemy1.png    ENEMY1     16x16     2           3       OK
bullet.png    BULLET     4x8       1           2       OK
Usage in ASM: 
include "sprites.asm"

ld hl, PLAYER
call |PSPRITE

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Example 2: Organized Sprites

Configuration:
devcpc.conf
MODE=0
SPRITES_PATH="assets/sprites"
SPRITES_OUT_FILE="ASM/graphics/sprites.asm"
SPRITES_TOLERANCE=-1  ; Auto-match colors
Directory structure: 
assets/sprites/
├── characters/
│   ├── player_walk1.png
│   ├── player_walk2.png
│   └── player_jump.png
├── enemies/
│   ├── bat.png
│   └── spider.png
└── items/
    ├── coin.png
    └── key.png
All PNG files are found recursively and converted to ASM/graphics/sprites.asm.

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Screen Conversion Examples

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Example 3: Loading Screens

Configuration:
devcpc.conf
MODE=0
LOADER_SCREEN="assets/screen"
Directory structure: 
assets/screen/
├── title.png       (160×200, 8 colors)
├── loading.png     (160×200, 4 colors)
└── credits.png     (160×200, 6 colors)
Build output: 
✓ 3 pantalla(s) convertida(s)

→ Añadiendo pantallas al DSK...
  title.scn
  loading.scn
  credits.scn
✓ 3 pantalla(s) añadida(s) al DSK
Generated files: 
obj/
├── title.scn       (16384 bytes)
├── title.scn.info  (palette info)
├── loading.scn
├── loading.scn.info
├── credits.scn
└── credits.scn.info
Usage in BASIC: 
10 MODE 0
20 LOAD"TITLE.SCN",&C000
30 REM Set palette from .scn.info
40 INK 0,0: INK 1,24: INK 2,6: INK 3,2
50 PAUSE 200

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Example 4: SCN Info File

Content of title.scn.info: 
FILE: title.scn
WIDTH: 160
HEIGHT: 200
MODE: 0
PALETTE COLORS: 8

FW              HW              RGB
0               0x14            (0, 0, 0)
24              0x0A            (255, 255, 0)
6               0x04            (255, 0, 0)
2               0x02            (0, 0, 255)

; ASM HW palette
db 0x14, 0x0A, 0x04, 0x02

' BASIC palette
INK 0,0: INK 1,24: INK 2,6: INK 3,2

// C palette
hwpal = { 0x14, 0x0A, 0x04, 0x02 }
Use this info to set the correct palette when loading the screen.

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Troubleshooting Graphics

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Error: Pillow Not Installed

Error: 
✗ Python Pillow no instalado
Solution: 
pip3 install Pillow

# Verify
python3 -c "import PIL; print('Pillow OK')"

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Error: Width Not Divisible

Error: 
✗ player.png: ancho 15 no divisible por 2 (MODE 0)
Solution: Adjust PNG width to meet mode requirements:
  • Mode 0: Width must be multiple of 2
  • Mode 1: Width must be multiple of 4
  • Mode 2: Width must be multiple of 8

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Error: Too Many Colors

Error: 
✗ sprite.png usa 18 INKs pero MODE 0 solo permite 16
Solution:
  1. Reduce colors in your PNG editor
  2. Use indexed color mode with CPC palette
  3. Or change to MODE 0 (16 colors) if using MODE 1/2

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Error: Color Not in Palette

Error: 
✗ Color RGB(200,100,50) no coincide con paleta CPC
Solution:
  1. Increase tolerance: SPRITES_TOLERANCE=16
  2. Use auto-match: SPRITES_TOLERANCE=-1
  3. Or adjust PNG colors to exact CPC palette values

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Error: Screen Wrong Resolution

Error: 
✗ title.png debe ser 160x200 para MODE 0
Solution: Screens must be exact resolution:
  • Mode 0: 160×200 pixels
  • Mode 1: 320×200 pixels
  • Mode 2: 640×200 pixels

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Tips

Use indexed PNG: Save PNGs with indexed color mode using the CPC palette for perfect conversion.
Organize by type: Keep sprites in assets/sprites/ and screens in assets/screen/ for clarity.
Check .scn.info: Always reference the .scn.info file for correct palette values when loading screens.
Test tolerance: Start with SPRITES_TOLERANCE=8. If colors don’t match, try -1 for auto-matching.

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Complete Graphics Example

devcpc.conf
# Project settings
PROJECT_NAME="space_game"
BUILD_LEVEL=0

# Graphics mode
MODE=0  # 160x200, 16 colors

# Sprite conversion
SPRITES_PATH="assets/sprites"
SPRITES_OUT_FILE="ASM/graphics/sprites.asm"
SPRITES_TOLERANCE=8
SPRITES_TRANSPARENT_INK=0  # Black = transparent

# Screen conversion
LOADER_SCREEN="assets/screen"

# Source paths
ASM_PATH="asm/make_all_space_game.asm"
BASIC_PATH="bas"
Project structure: 
space_game/
├── devcpc.conf
├── assets/
│   ├── sprites/
│   │   ├── ship.png
│   │   ├── enemies/
│   │   │   ├── alien1.png
│   │   │   └── alien2.png
│   │   └── bullets/
│   │       └── laser.png
│   └── screen/
│       ├── title.png
│       └── gameover.png
├── ASM/
│   ├── make_all_space_game.asm
│   └── graphics/
│       └── sprites.asm  (generated)
└── bas/
    └── loader.bas
Build process: 
devcpc build
# 1. Converts all PNGs in assets/sprites/ → ASM/graphics/sprites.asm
# 2. Converts all PNGs in assets/screen/ → obj/*.scn + obj/*.scn.info
# 3. Compiles ASM (includes sprites.asm)
# 4. Adds BASIC and SCN files to DSK

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See Also

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