PaletteViewerPanel.java

package com.rox.ppu.debug;

import com.rox.ppu.NesPalette;

import com.rox.ppu.PPU;

import javax.swing.JLabel;

import javax.swing.JPanel;

import javax.swing.SwingConstants;

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.Dimension;

import java.awt.GridLayout;

/**

 * All 8 of the PPU's palettes ({@code $3F00-$3F1F}) at once, one row per palette (background palettes

 * 0-3, then sprite palettes 0-3 - the same 8 names as {@link ChrViewerPanel}'s selector), each row

 * labelled to its left and gapped from its neighbours for readability. A header row along the top

 * numbers the 4 swatch columns, aligned with the swatches beneath it - both the header and every row

 * lay their 4 columns out with a plain {@link GridLayout} that always fills 100% of its available

 * width, rather than one of them centering a scaled image within its own space, so the columns can't

 * drift out of alignment regardless of how much extra width/height the sidebar ends up giving this

 * panel. Colours are resolved live from {@link PPU#paletteSnapshot()} through {@code NesPalette} via

 * {@link #refresh()}, called once per frame by {@link PpuDebugFrame}'s timer. Swatch 0 of each Sprite

 * row mirrors swatch 0 of its corresponding Background row (Sprite 1's colour 0 is Background 1's, not

 * Background 0's) - real hardware's backdrop-mirror quirk pairs each sprite palette with its

 * same-numbered background palette, not all 8 with a single shared entry (see

 * {@link PPU#paletteSnapshot()}'s own documentation).

 */

final class PaletteViewerPanel extends JPanel {

    private static final int COLORS_PER_PALETTE = 4;

    private static final int SWATCH_PX = 24;

    private static final int ROW_GAP_PX = 8;

    private static final float LABEL_FONT_SIZE = 24f;

    private static final int SWATCHES_WIDTH_PX = COLORS_PER_PALETTE * SWATCH_PX;

    private final PPU ppu;

    private final int labelColumnPx;

    private final PaletteRow[] rows = new PaletteRow[ChrViewerPanel.PALETTE_NAMES.length];

    PaletteViewerPanel(final PPU ppu){

        this.ppu = ppu;

        this.labelColumnPx = widestLabelWidth();

        setLayout(new BorderLayout());

        add(header(), BorderLayout.NORTH);

        final JPanel rowsPanel = new JPanel(new GridLayout(rows.length, 1, 0, ROW_GAP_PX));

        for (int paletteIndex = 0; paletteIndex < rows.length; paletteIndex++){

            rows[paletteIndex] = new PaletteRow(ChrViewerPanel.PALETTE_NAMES[paletteIndex]);

            rowsPanel.add(rows[paletteIndex]);

        }

        add(rowsPanel, BorderLayout.CENTER);

        refresh();

    }

    /** Pulls the PPU's current palette RAM into every row's swatches - called once per frame, not on every repaint, since colours only change when the game writes new ones. */

    void refresh(){

        final int[] paletteSnapshot = ppu.paletteSnapshot();

        for (int paletteIndex = 0; paletteIndex < rows.length; paletteIndex++){

            rows[paletteIndex].refresh(paletteSnapshot, paletteIndex * COLORS_PER_PALETTE);

        }

    }

    /** Width (in px) of the widest palette name at {@link #LABEL_FONT_SIZE} - keeps every row's label column, and the header's spacer above them, the same width so the swatch columns line up. */

    private static int widestLabelWidth(){

        final JLabel measuring = new JLabel();

        measuring.setFont(measuring.getFont().deriveFont(LABEL_FONT_SIZE));

        int widest = 0;

        for (final String name : ChrViewerPanel.PALETTE_NAMES){

            measuring.setText(name);

            widest = Math.max(widest, measuring.getPreferredSize().width);

        }

        return widest;

    }

    /** A blank spacer matching the row labels' width, plus swatch-column numbers 0-3 above the swatches. */

    private JPanel header(){

        final JPanel spacer = new JPanel();

        spacer.setPreferredSize(new Dimension(labelColumnPx, 1));

        final JPanel numbers = new JPanel(new GridLayout(1, COLORS_PER_PALETTE));

        numbers.setPreferredSize(new Dimension(SWATCHES_WIDTH_PX, 1));

        for (int color = 0; color < COLORS_PER_PALETTE; color++){

            final JLabel number = new JLabel(String.valueOf(color), SwingConstants.CENTER);

            number.setFont(number.getFont().deriveFont(LABEL_FONT_SIZE));

            numbers.add(number);

        }

        final JPanel header = new JPanel(new BorderLayout());

        header.add(spacer, BorderLayout.WEST);

        header.add(numbers, BorderLayout.CENTER);

        return header;

    }

    /** One palette's name label plus its 4-swatch strip, side by side. */

    private final class PaletteRow extends JPanel {

            }

        void refresh(final int[] paletteSnapshot, final int base){

            }

    }

}

Mutations