Bitmap

Struct · namespace Amiga · AmigaOS only · Since 0.20

struct Bitmap

A picture in chip memory: Depth bitplanes of Width x Height pixels, one after the other (plane p starts at Plane(p)). Width is a multiple of 16.

Fields

Name	Description
Width	The width in pixels (a multiple of 16).
Height	The height in pixels.
Depth	The number of bitplanes (1 to 6): the bitmap has 2^Depth colors.
BytesPerRow	The bytes of one row of a plane (Width / 8).
PlaneSize	The bytes of one plane (BytesPerRow * Height).

Width

int Width

The width in pixels (a multiple of 16).

Height

int Height

The height in pixels.

Depth

int Depth

The number of bitplanes (1 to 6): the bitmap has 2^Depth colors.

BytesPerRow

int BytesPerRow

The bytes of one row of a plane (Width / 8).

PlaneSize

int PlaneSize

The bytes of one plane (BytesPerRow * Height).

Static methods

Name	Description
Create	A cleared bitmap in chip memory.

Create

static Optional<Bitmap> Create(int width, int height, int depth)

A cleared bitmap in chip memory.

Parameters

• width: a multiple of 16, up to 1024.
• height: up to 1024.
• depth: the number of bitplanes, 1 to 6.

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

Panics when a size is out of range.

Methods

Name	Description
Free	Gives the chip memory back (after the blitter is done with it).
Plane	The address of bitplane p (0 to Depth - 1).
Clear	Sets all pixels to color 0 (with the blitter).
FillRect	A filled rectangle of w x h pixels at (x, y) in color (with the blitter).
DrawRect	The outline of a rectangle of w x h pixels at (x, y) in color.
SetPixel	Sets the pixel at (x, y) to color (nothing happens outside of the bitmap).
GetPixel	The color of the pixel at (x, y).
DrawLine	A line from (x0, y0) to (x1, y1) in color, both ends included.
DrawPattern	Pixels from text, one string per row: ‘0’..‘9’ and ‘A’..‘V’ are the colors 0..31, every other character (‘.’, ’ ’) leaves the pixel as it is.
Copy	Copies w x h pixels from (sx, sy) of source to (x, y) (the planes both have; source and destination must not overlap).
DrawMasked	Draws a shape (a “bob”): w x h pixels from (sx, sy) of source to (x, y), only where mask (a bitmap with one plane, the same size as source, e.g. source.MakeMask()) has a 1.
MakeMask	A mask for DrawMasked: a bitmap with one plane that is 1 where this bitmap’s color is not 0; null if there is not enough chip memory.
DrawText	Text in the system font (Topaz 8 or the font set in the preferences), at (x, y) = the top left corner of the first character; the pixels around the letters stay.

Free

void Free()

Gives the chip memory back (after the blitter is done with it).

Plane

uint8* Plane(int p)

The address of bitplane p (0 to Depth - 1).

Clear

void Clear()

Sets all pixels to color 0 (with the blitter).

FillRect

void FillRect(int x, int y, int w, int h, int color)

A filled rectangle of w x h pixels at (x, y) in color (with the blitter).

DrawRect

void DrawRect(int x, int y, int w, int h, int color)

The outline of a rectangle of w x h pixels at (x, y) in color.

SetPixel

void SetPixel(int x, int y, int color)

Sets the pixel at (x, y) to color (nothing happens outside of the bitmap).

GetPixel

int GetPixel(int x, int y)

The color of the pixel at (x, y).

Returns 0 outside of the bitmap.

DrawLine

void DrawLine(int x0, int y0, int x1, int y1, int color)

A line from (x0, y0) to (x1, y1) in color, both ends included.

DrawPattern

void DrawPattern(int x, int y, ReadOnlySlice<StringSlice> rows)

Pixels from text, one string per row: ‘0’..‘9’ and ‘A’..‘V’ are the colors 0..31, every other character (‘.’, ’ ’) leaves the pixel as it is.

void DrawPattern(int x, int y, ReadOnlySlice<string> rows)

The same with the rows as strings, e.g. the lines of a file: const ReadOnlySlice<string> Ball = embed_lines("ball.txt"); … bitmap.DrawPattern(0, 0, Ball);

void DrawPattern(int x, int y, int width, ReadOnlySlice<uint8> pattern)

Draws a given color pattern. Each byte in the pattern gives a color index (0..31). Higher values are ignored (not drawn).

If the number of given color indices is not a multiple of width, the last row is still partially drawn.

Parameters

• x: x coordinate.
• y: y coordinate.
• width: (row) width.
• pattern: the given color indices.

Since 0.25

Copy

void Copy(const ref Bitmap source, int sx, int sy, int x, int y, int w, int h)

Copies w x h pixels from (sx, sy) of source to (x, y) (the planes both have; source and destination must not overlap). The blitter does it when x % 16 >= sx % 16 (e.g. sources at multiples of 16), the CPU otherwise; it is fastest for whole words (x, sx and w multiples of 16).

DrawMasked

void DrawMasked(const ref Bitmap source, const ref Bitmap mask, int sx, int sy, int x, int y, int w, int h)

Draws a shape (a “bob”): w x h pixels from (sx, sy) of source to (x, y), only where mask (a bitmap with one plane, the same size as source, e.g. source.MakeMask()) has a 1. sx must be a multiple of 16; the pixels right of the shape up to the next multiple of 16 are drawn too where the mask has a 1. The blitter does it when the shape is inside the bitmap from left to right, the CPU otherwise.

MakeMask

Optional<Bitmap> MakeMask()

A mask for DrawMasked: a bitmap with one plane that is 1 where this bitmap’s color is not 0; null if there is not enough chip memory.

DrawText

int DrawText(int x, int y, StringSlice text, int color)

Text in the system font (Topaz 8 or the font set in the preferences), at (x, y) = the top left corner of the first character; the pixels around the letters stay. UTF-8 characters up to U+00FF are shown, others as ‘?’. The x after the text is returned.