The sparkmaker uses G-files with embedded binary bitmaps for the layers.
Disclaimer: My Sparkmaker has not arrived yet and this is all based on working with .wow files only. Although, I was successful in recovering an image of the layer from the binary blob. It is provided "AS IS" without warranty of any kind.
G21; set unit to mm
G91; incremental positioning
M17; enable stepper motor
M106 S0; LED intesity to 0 --> off
G28 Z0; homing of Z axis
;W:480; | resolution of the display
;H:854; | in the follwing the axes of the layer are called W and H
;L:1; layer number (begins with 1)
M106 S0; LED off
G1 Z10 F50; lift Z axis by 10mm("Lift Distance") with speed 50mm/min("Lift Speed")
G1 Z-9.975 F150; drop Z axis by 10mm-layer height ("Layer Thickness") with speed 150mm/min (decline speed)
{{
BINARYLAYER
}}
M106 S255; LED on with intensity 255 ("Exposure Strength Grade")
G4 S25; wait for 25s ("Exposure Time Per Layer"/"Bottom Layer Exposure Time")
Inbetween the brackets the layer is written as binary bytes. Each pixel is either 0 or 1 and 8 pixel in the W dimension are written as one byte. After 480 pixels (60 bytes) with W = 0 to 479 are written for a line with H=h, the next line with H=h+1 is wirtten the same way.
------------------ | -------------- | | ----------------- | ------------- |
W0H0 W1H0 ... W7H0 | W8H0 ... W15H0 | ... | W471H0 ... W479H0 | W0H1 ... W7H1 | ...
------------------ | -------------- | | ----------------- | ------------- |
Byte 0 Byte 1 Byte 59 Byte 60
M106 S0; LED PWM to 0 --> off
G1 Z20.0; lift Z axis by 20mm
G4 S300; wait for 300s
M18; disable stepper motor