While some Spanish companies reduced the screen in order to get the game better running in low-spec 464, the infamous speccy ports just ran a reduced screen so the ZX Spectrum's code and graphics could run almost "unchanged".
==Real-Time Conversion of 1bpp Spectrum graphics==
A common way to get the Speccy game running on a the CPC was to get some routine to convert the existing and already coded 1bpp Speccy's Graphic Data (tiles and sprites in equivalent to Mode2 on CPC) into 2bpp datas (proper Mode1) when put into the video RAM. Needless to say, this enabled the port without the use perform real-time conversion of additional Spectrum graphics artists, or a coder to redo the RAM mapping/addresses of such data.
But this came at a cost* Graphics are stored on the Amstrad in the same format as on the Spectrum (2 colour, CPU1BPP)* Amstrad's mode 1 is used to maintain the same pixel resolution.* A routine converts the graphics on-wise since demand, while the CPU instead of simply having to take some bytes of data from reserve game is running, into the Video RAM has form that is displayed for the screen. Needless to convert them in real timesay, with this enabled the port without the result being that a character couldn't use/display of additional graphics artists, so it was cheaper. Disadvantages:* This process takes a lot more than 2 colours while CPC 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 slower game.* Amstrad version had not such thing less colours (often as character attributeslittle as 2 colours) Advantages:* Pixel data took less RAM compared to storing it in Amstrad's mode 1 form.
==Monochromatic playfield and Sprite Masks==
