Mosaicus
Contents›Painting›Image stamp

Image stamp

The Image stamp (K) places another picture into yours: a logo, an icon, a signature, a sprite you drew elsewhere. Choose the picture, set its size, and click to stamp it wherever you want, as many times as you like.

Choosing the picture

Click Picture… on the options bar and choose a PNG, JPEG, WebP, GIF or BMP file. Its name shows next to the button; hover over the name to see its size in pixels and whether it has transparency of its own.

Mosaicus prepares the picture as soon as you choose it:

  • What is see-through. A picture with transparency of its own (a PNG with an alpha channel) keeps it. Any other picture has its background worked out: the most common color round its edges becomes transparent, and soft edges fade into it.
  • Trimmed. The see-through margins are cut off, so the stamp is just what shows.
  • Sized. If the picture fits in yours one pixel for one pixel, it comes in at 1:1 with hard edges, so pixel art stays exactly as it was drawn. On wide pixels (multicolor), a picture drawn with doubled pixels is recognized: two of its pixels become one wide pixel. A picture too big for 1:1 starts at 40% of your picture's width (or its height, if that is what limits it).

A very large picture is reduced to 4,096 pixels on its longer side when it is read. The chosen picture stays loaded while the app is open, but it isn't saved with the project.

Placing it

Move the pointer over the picture: the stamp follows it, centered on the pointer, exactly as it will be stamped. Click to stamp it. The stamp keeps following the pointer for the next one.

Clicking with the right button swaps the paint colors for that stamp: it matters for the fill style, the outline and the shadow. Alt+click picks up a color instead, as the Eyedropper does.

Size

  • W sets the width in your picture's pixels, and H the height in lines. Change one and the other follows, keeping the picture's shape as it looks on the screen (wide pixels and the pixel aspect counted). Each can be 1 to 1,024.
  • 1:1 sets the size as drawn: one of its pixels to one of yours (on wide pixels, two of its own where it was drawn with doubled pixels).

A stamp is scaled down in halves, then to the size, so a big picture made small loses none of its parts. At a whole multiple of its size, or at 1:1, its pixels are kept as they are, not smoothed.

Its colors

Colors chooses what the stamp is painted in:

  • Its own (the default): each of its colors becomes the nearest color the picture may use. Dither chooses how:
    • None (nearest color) (the default): each pixel the nearest allowed color.
    • Error diffusion (Floyd–Steinberg, Atkinson, Sierra and others): each pixel's error spreads to the next ones, keeping the picture's own shading. Amount (0 to 100%, the default 100%) sets how much of the error spreads: less is cleaner, more is smoother. In formats with cell limits, the cells' colors are chosen first, as the converter does (in Multicolor and ECM characters, the cells are recolored afterward instead).
    • Ordered dithers (Bayer 2 × 2, 4 × 4 and 8 × 8, clustered dots, lines, blue noise, random): a regular pattern that lines up with your fills and patterns wherever you stamp.
  • The fill style: the stamp is a stencil, its shape painted in the Image stamp's own fill style (the primary color, a pattern, a dither mix, a gradient and so on; see Fill). With a dither mix, Shift+[ and Shift+] change its level.

Style: see-through, edges, outline and shadow

The style pop-up (its button names the settings, for example Edges: blended) has:

  • See-through: Its background color (the default for a picture without transparency) or Its own transparency (the default for one with an alpha channel).
  • Background (with Its background color): the color that becomes transparent: The commonest round its edges (the default), Black or White.
  • Edges: how its soft edges land on whole pixels.
    • Hard (whole pixels): a pixel shows when it is at least half covered. A picture that came in at 1:1 starts with hard edges.
    • Smooth, dithered: partly covered pixels are dithered.
    • Smooth, blended to the nearest color (the default otherwise): partly covered pixels take the color nearest to a blend with what is under them.
  • Outline: a one-pixel outline all round, in the secondary color.
  • Shadow: a one-pixel shadow down and to the right, in the secondary color.

Cell limits

Cells says what happens when the stamp's colors are too many for a cell. A stamp is planned cell by cell, like a fill: in Recolor cells mode each cell keeps the colors that lose the least, and every pixel takes its nearest color the cell can have. See Cell limits and clashes.

TipFor a logo in a multicolor picture, draw it at the format's size (160 pixels across is the whole width) with doubled pixels, in C64 colors. It then comes in at 1:1 with hard edges, pixel for pixel.

  • Text: stamping letters the same way.
  • Cut, copy and paste: pasting a picture from another program as a floating piece you can move, turn and scale.
  • Opening pictures: converting a whole picture rather than stamping one.