Screen

Struct · namespace Amiga · AmigaOS only · Since 0.20

struct Screen

A low resolution PAL screen: a bitmap (two with double buffering) shown by a copper list that also sets the palette and the sprites. With Bitmap, Blitter, Sprite, CopperList and SystemFont it is the graphics on the Amiga’s custom chips (only for amigaos targets, after Hardware.TakeOver).

using Amiga;

Hardware.TakeOver();
if (Screen.Open(320, 256, 4, true) is Screen screen)
{
    screen.SetColor(1, 0xFFF);
    screen.Show();
    while (!Hardware.LeftMouseButton())
    {
        screen.Back.Clear();                            // the blitter
        screen.Back.FillRect(10, 10, 100, 50, 2);
        screen.Back.DrawText(20, 100, "Hello", 1);     // Topaz, from the ROM
        screen.Swap();                                  // shows Back, waits for the vertical blank
    }
    Hardware.Restore();
    screen.Close();
}

Coordinates are pixels, (0, 0) is the top left corner; drawing is clipped to the bitmap. Colors are numbers of the palette (0 .. 2^depth - 1); the palette has 12-bit colors (0xRGB).

Fields

Name	Description
Front	The bitmap that is shown.
Back	The bitmap to draw into; the same as Front without double buffering.
Copper	The copper list of the screen.
Width	The width in pixels.
Height	The height in pixels.
Depth	The number of bitplanes.

Front

Bitmap Front

The bitmap that is shown.

Back

Bitmap Back

The bitmap to draw into; the same as Front without double buffering.

Copper

CopperList Copper

The copper list of the screen. After the setup it takes your own instructions (Copper.Wait(y), Copper.Color(0, 0xF00), …; Copper.Reset() removes them again).

Width

int Width

The width in pixels.

Height

int Height

The height in pixels.

Depth

int Depth

The number of bitplanes.

Static methods

Name	Description
Open	Opens a low resolution PAL screen: a bitmap (two with doubleBuffer) shown by a copper list that also sets the palette and the sprites.

Open

static Optional<Screen> Open(int width, int height, int depth, bool doubleBuffer)

Opens a low resolution PAL screen: a bitmap (two with doubleBuffer) shown by a copper list that also sets the palette and the sprites.

Parameters

• width: a multiple of 16, 128 to 320.
• height: 1 to 256.
• depth: 1 to 5 (2 to 32 colors).
• doubleBuffer: draw into Back while Front is shown, and swap them with Screen.Swap.

Returns nothing (null) if there is not enough chip memory.

Panics when a size is out of range.

Methods

Name	Description
SetColor	color 0..31 as 0xRGB (from the next frame on)
Show	Shows the screen: starts its copper list and the DMA for bitplanes, copper, blitter and sprites (after Hardware.TakeOver).
Swap	Shows Back from the next frame on (Front and Back swap) and waits for the vertical blank: then the new Back is no longer on the screen.
ShowSprite	sprite ‘number’ (0..7) shows sprite (from the next frame on)
HideSprite	Hides sprite number (0 to 7) from the next frame on.
Close	frees the bitmaps and the copper list (after Hardware.Restore, when the screen is no longer shown)

SetColor

void SetColor(int index, int rgb)

color 0..31 as 0xRGB (from the next frame on)

Show

void Show()

Shows the screen: starts its copper list and the DMA for bitplanes, copper, blitter and sprites (after Hardware.TakeOver).

Swap

void Swap()

Shows Back from the next frame on (Front and Back swap) and waits for the vertical blank: then the new Back is no longer on the screen. Without double buffering it only waits.

ShowSprite

void ShowSprite(int number, Sprite sprite)

sprite ‘number’ (0..7) shows sprite (from the next frame on)

HideSprite

void HideSprite(int number)

Hides sprite number (0 to 7) from the next frame on.

Close

void Close()

frees the bitmaps and the copper list (after Hardware.Restore, when the screen is no longer shown)