=====Real-Time Conversion of Spectrum graphics=====
A common way to get the Speccy game running on the CPC and using the same storage space for the graphics was to perform real-time conversion of from the Spectrum graphics.
* Graphics are stored on the Amstrad in the same format as on the Spectrum (2 colour, 1BPPwith sprites having masks)
* Amstrad's mode 1 is used to maintain the same pixel resolution.
* A routine function converts the graphics on-demand, while the game is running, into the form that is displayed for the screen.
Needless to say, this enabled the port without the use of additional graphics artists so . Therefore it was would be cheaper and easier if a programmer was tasked with making a conversion alone.
Disadvantages:
* This process takes a lot more CPU power compared to the Spectrum version, because in addition to drawing and erasing the sprites, the pixel data must also be converted at the same time.
* This resulted in a significantly slower game.
* Amstrad version had less colours (often as little as 2 colours)
Advantages:
* Pixel data took less RAM compared to storing than if it was stored in an Amstrad's mode 1 native form, so the game could run on a 64K Ram machine (CPC464 and CPC664, 464Plus).* If the colour attributes of the Spectrum were not simulated then the attribute data would not need to be stored for the CPC.
=====Mode 1 and screen dimensions=====