UIDefaultsLoader: added contrast() color function (inspired by Less CSS), which is useful to choose a foreground color that is readable, based on the luma (perceptual brightness) of a background color

This commit is contained in:
Karl Tauber
2021-08-30 23:58:37 +02:00
parent 9b465cb550
commit 7f9cf6f45c
9 changed files with 180 additions and 18 deletions

View File

@@ -611,6 +611,7 @@ class UIDefaultsLoader
case "mix": return parseColorMix( null, params, resolver, reportError );
case "tint": return parseColorMix( "#fff", params, resolver, reportError );
case "shade": return parseColorMix( "#000", params, resolver, reportError );
case "contrast": return parseColorContrast( params, resolver, reportError );
}
} finally {
parseColorDepth--;
@@ -804,14 +805,10 @@ class UIDefaultsLoader
if( color1Str == null )
color1Str = params.get( i++ );
String color2Str = params.get( i++ );
int weight = 50;
if( params.size() > i )
weight = parsePercentage( params.get( i++ ) );
int weight = (params.size() > i) ? parsePercentage( params.get( i ) ) : 50;
// parse second color
String resolvedColor2Str = resolver.apply( color2Str );
ColorUIResource color2 = (ColorUIResource) parseColorOrFunction( resolvedColor2Str, resolver, reportError );
ColorUIResource color2 = (ColorUIResource) parseColorOrFunction( resolver.apply( color2Str ), resolver, reportError );
if( color2 == null )
return null;
@@ -822,6 +819,34 @@ class UIDefaultsLoader
return parseFunctionBaseColor( color1Str, function, false, resolver, reportError );
}
/**
* Syntax: contrast(color,dark,light[,threshold])
* - color: a color to compare against
* - dark: a designated dark color (e.g. #000) or a color function
* - light: a designated light color (e.g. #fff) or a color function
* - threshold: the threshold (in range 0-100%) to specify where the transition
* from "dark" to "light" is (default is 43%)
*/
private static Object parseColorContrast( List<String> params, Function<String, String> resolver, boolean reportError ) {
String colorStr = params.get( 0 );
String darkStr = params.get( 1 );
String lightStr = params.get( 2 );
int threshold = (params.size() > 3) ? parsePercentage( params.get( 3 ) ) : 43;
// parse color to compare against
ColorUIResource color = (ColorUIResource) parseColorOrFunction( resolver.apply( colorStr ), resolver, reportError );
if( color == null )
return null;
// check luma and determine whether to use dark or light color
String darkOrLightColor = (ColorFunctions.luma( color ) * 100 < threshold)
? lightStr
: darkStr;
// parse dark or light color
return parseColorOrFunction( resolver.apply( darkOrLightColor ), resolver, reportError );
}
private static Object parseFunctionBaseColor( String colorStr, ColorFunction function,
boolean derived, Function<String, String> resolver, boolean reportError )
{

View File

@@ -79,6 +79,34 @@ public class ColorFunctions
Math.round( a2 + ((a1 - a2) * weight) ) );
}
/**
* Calculates the luma (perceptual brightness) of the given color.
* <p>
* Uses SMPTE C / Rec. 709 coefficients, as recommended in
* <a href="https://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef">WCAG 2.0</a>.
*
* @param color a color
* @return the luma (in range 0-1)
*
* @see <a href="https://en.wikipedia.org/wiki/Luma_(video)">https://en.wikipedia.org/wiki/Luma_(video)</a>
* @since 1.6
*/
public static float luma( Color color ) {
// see https://en.wikipedia.org/wiki/Luma_(video)
// see https://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef
// see https://github.com/less/less.js/blob/master/packages/less/src/less/tree/color.js
float r = gammaCorrection( color.getRed() / 255f );
float g = gammaCorrection( color.getGreen() / 255f );
float b = gammaCorrection( color.getBlue() / 255f );
return (0.2126f * r) + (0.7152f * g) + (0.0722f * b);
}
private static float gammaCorrection( float value ) {
return (value <= 0.03928f)
? value / 12.92f
: (float) Math.pow( (value + 0.055) / 1.055, 2.4 );
}
//---- interface ColorFunction --------------------------------------------
public interface ColorFunction {

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@@ -0,0 +1,44 @@
/*
* Copyright 2021 FormDev Software GmbH
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.formdev.flatlaf.util;
import static org.junit.jupiter.api.Assertions.assertEquals;
import java.awt.Color;
import org.junit.jupiter.api.Test;
/**
* @author Karl Tauber
*/
public class TestColorFunctions
{
@Test
void luma() {
assertEquals( 0, ColorFunctions.luma( Color.black ) );
assertEquals( 1, ColorFunctions.luma( Color.white ) );
assertEquals( 0.2126f, ColorFunctions.luma( Color.red ) );
assertEquals( 0.7152f, ColorFunctions.luma( Color.green ) );
assertEquals( 0.0722f, ColorFunctions.luma( Color.blue ) );
assertEquals( 0.9278f, ColorFunctions.luma( Color.yellow ) );
assertEquals( 0.7874f, ColorFunctions.luma( Color.cyan ) );
assertEquals( 0.051269464f, ColorFunctions.luma( Color.darkGray ) );
assertEquals( 0.21586052f, ColorFunctions.luma( Color.gray ) );
assertEquals( 0.52711517f, ColorFunctions.luma( Color.lightGray ) );
}
}

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@@ -471,6 +471,12 @@ class FlatCompletionProvider
addFunction( "shade",
"color", colorParamDesc,
"weight", weightParamDesc );
addFunction( "contrast",
"color", colorParamDesc,
"dark", colorParamDesc,
"light", colorParamDesc,
"threshold", "(optional) 0-100%, default is 43%" );
}
private void addFunction( String name, String... paramNamesAndDescs ) {

View File

@@ -31,6 +31,7 @@ import org.fife.ui.rsyntaxtextarea.Token;
import com.formdev.flatlaf.FlatLaf;
import com.formdev.flatlaf.UIDefaultsLoaderAccessor;
import com.formdev.flatlaf.ui.FlatUIUtils;
import com.formdev.flatlaf.util.ColorFunctions;
import com.formdev.flatlaf.util.HSLColor;
import com.formdev.flatlaf.util.UIScale;
@@ -46,6 +47,7 @@ class FlatThemeEditorOverlay
static boolean showHSL = true;
static boolean showRGB;
static boolean showLuma;
private Font font;
private Font baseFont;
@@ -80,19 +82,21 @@ class FlatThemeEditorOverlay
}
FontMetrics fm = c.getFontMetrics( font );
int space = fm.stringWidth( " " );
int maxTextWidth = 0;
if( showHSL )
maxTextWidth += fm.stringWidth( "HSL 360 100 100" );
maxTextWidth += fm.stringWidth( "HSL 360 100 100" ) + space;
if( showRGB )
maxTextWidth += fm.stringWidth( "#ffffff" );
if( showHSL && showRGB )
maxTextWidth += fm.stringWidth( " " );
maxTextWidth += fm.stringWidth( "#ffffff" ) + space;
if( showLuma )
maxTextWidth += fm.stringWidth( "100" ) + space;
maxTextWidth = Math.max( maxTextWidth - space, 0 );
int textHeight = fm.getAscent() - fm.getLeading();
int width = c.getWidth();
int previewWidth = UIScale.scale( COLOR_PREVIEW_WIDTH );
int gap = UIScale.scale( 4 );
int textGap = (showHSL || showRGB) ? UIScale.scale( 6 ) : 0;
int textGap = (showHSL || showRGB || showLuma) ? UIScale.scale( 6 ) : 0;
// check whether preview is outside of clip bounds
if( clipBounds.x + clipBounds.width < width - previewWidth - maxTextWidth - gap - textGap )
@@ -123,7 +127,7 @@ class FlatThemeEditorOverlay
}
// paint text
if( showHSL || showRGB ) {
if( showHSL || showRGB || showLuma ) {
int textX = px - textGap - maxTextWidth;
if( textX > r.x + gap) {
String colorStr = null;
@@ -141,6 +145,14 @@ class FlatThemeEditorOverlay
else
colorStr = rgbStr;
}
if( showLuma ) {
String lumaStr = String.format( "%3d",
Math.round( ColorFunctions.luma( color ) * 100 ) );
if( colorStr != null )
colorStr += " " + lumaStr;
else
colorStr = lumaStr;
}
int textWidth = fm.stringWidth( colorStr );
if( textWidth > maxTextWidth )

View File

@@ -83,8 +83,9 @@ class FlatThemeFileEditor
private static final String KEY_PREVIEW = "preview";
private static final String KEY_LAF = "laf";
private static final String KEY_FONT_SIZE_INCR = "fontSizeIncr";
private static final String KEY_HSL_COLORS = "hslColors";
private static final String KEY_RGB_COLORS = "rgbColors";
private static final String KEY_SHOW_HSL_COLORS = "showHslColors";
private static final String KEY_SHOW_RGB_COLORS = "showRgbColors";
private static final String KEY_SHOW_COLOR_LUMA = "showColorLuma";
private File dir;
private Preferences state;
@@ -701,9 +702,11 @@ class FlatThemeFileEditor
private void colorModelChanged() {
FlatThemeEditorOverlay.showHSL = showHSLColorsMenuItem.isSelected();
FlatThemeEditorOverlay.showRGB = showRGBColorsMenuItem.isSelected();
FlatThemeEditorOverlay.showLuma = showColorLumaMenuItem.isSelected();
putPrefsBoolean( state, KEY_HSL_COLORS, FlatThemeEditorOverlay.showHSL, true );
putPrefsBoolean( state, KEY_RGB_COLORS, FlatThemeEditorOverlay.showRGB, false );
putPrefsBoolean( state, KEY_SHOW_HSL_COLORS, FlatThemeEditorOverlay.showHSL, true );
putPrefsBoolean( state, KEY_SHOW_RGB_COLORS, FlatThemeEditorOverlay.showRGB, false );
putPrefsBoolean( state, KEY_SHOW_COLOR_LUMA, FlatThemeEditorOverlay.showLuma, false );
repaint();
}
@@ -755,13 +758,15 @@ class FlatThemeFileEditor
directoryField.setModel( model );
// restore overlay color models
FlatThemeEditorOverlay.showHSL = state.getBoolean( KEY_HSL_COLORS, true );
FlatThemeEditorOverlay.showRGB = state.getBoolean( KEY_RGB_COLORS, false );
FlatThemeEditorOverlay.showHSL = state.getBoolean( KEY_SHOW_HSL_COLORS, true );
FlatThemeEditorOverlay.showRGB = state.getBoolean( KEY_SHOW_RGB_COLORS, false );
FlatThemeEditorOverlay.showLuma = state.getBoolean( KEY_SHOW_COLOR_LUMA, false );
// restore menu item selection
previewMenuItem.setSelected( state.getBoolean( KEY_PREVIEW, true ) );
showHSLColorsMenuItem.setSelected( FlatThemeEditorOverlay.showHSL );
showRGBColorsMenuItem.setSelected( FlatThemeEditorOverlay.showRGB );
showColorLumaMenuItem.setSelected( FlatThemeEditorOverlay.showLuma );
}
private void saveState() {
@@ -877,6 +882,7 @@ class FlatThemeFileEditor
resetFontSizeMenuItem = new JMenuItem();
showHSLColorsMenuItem = new JCheckBoxMenuItem();
showRGBColorsMenuItem = new JCheckBoxMenuItem();
showColorLumaMenuItem = new JCheckBoxMenuItem();
windowMenu = new JMenu();
activateEditorMenuItem = new JMenuItem();
nextEditorMenuItem = new JMenuItem();
@@ -1024,6 +1030,11 @@ class FlatThemeFileEditor
showRGBColorsMenuItem.setText("Show RGB colors (hex)");
showRGBColorsMenuItem.addActionListener(e -> colorModelChanged());
viewMenu.add(showRGBColorsMenuItem);
//---- showColorLumaMenuItem ----
showColorLumaMenuItem.setText("Show color luma");
showColorLumaMenuItem.addActionListener(e -> colorModelChanged());
viewMenu.add(showColorLumaMenuItem);
}
menuBar.add(viewMenu);
@@ -1133,6 +1144,7 @@ class FlatThemeFileEditor
private JMenuItem resetFontSizeMenuItem;
private JCheckBoxMenuItem showHSLColorsMenuItem;
private JCheckBoxMenuItem showRGBColorsMenuItem;
private JCheckBoxMenuItem showColorLumaMenuItem;
private JMenu windowMenu;
private JMenuItem activateEditorMenuItem;
private JMenuItem nextEditorMenuItem;

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@@ -177,6 +177,11 @@ new FormModel {
"text": "Show RGB colors (hex)"
addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "colorModelChanged", false ) )
} )
add( new FormComponent( "javax.swing.JCheckBoxMenuItem" ) {
name: "showColorLumaMenuItem"
"text": "Show color luma"
addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "colorModelChanged", false ) )
} )
} )
add( new FormContainer( "javax.swing.JMenu", new FormLayoutManager( class javax.swing.JMenu ) ) {
name: "windowMenu"

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@@ -71,6 +71,7 @@ public class FlatThemeTokenMaker
tokenMap.put( "mix", TOKEN_FUNCTION );
tokenMap.put( "tint", TOKEN_FUNCTION );
tokenMap.put( "shade", TOKEN_FUNCTION );
tokenMap.put( "contrast", TOKEN_FUNCTION );
tokenMap.put( "lazy", TOKEN_FUNCTION );
// function options

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@@ -70,3 +70,32 @@ Prop.colorFunc42 = tint(#f0f,75%)
Prop.colorFunc45 = shade(#f0f,25%)
Prop.colorFunc46 = shade(#f0f)
Prop.colorFunc47 = shade(#f0f,75%)
Prop.colorFunc50 = contrast(#111,#000,#fff)
Prop.colorFunc51 = contrast(#eee,#000,#fff)
Prop.colorFunc52 = contrast(#111,$Prop.colorFunc1,$Prop.colorFunc3)
Prop.colorFunc53 = contrast(#eee,$Prop.colorFunc1,$Prop.colorFunc3)
Prop.colorFunc54 = contrast(lighten(#111,5%),$Prop.colorFunc1,$Prop.colorFunc3)
Prop.colorFunc55 = contrast(lighten(#eee,5%),$Prop.colorFunc1,$Prop.colorFunc3)
Prop.colorFunc56 = contrast(contrast(#222,#111,#eee),contrast(#eee,#000,#fff),contrast(#111,#000,#fff))
Prop.1.selectionBackground = #2675BF
Prop.1.selectionForeground = contrast($Prop.1.selectionBackground,#000,#fff)
Prop.2.selectionBackground = #95c0e9
Prop.2.selectionForeground = contrast($Prop.2.selectionBackground,#000,#fff)
Prop.3.selectionBackground = #f00
Prop.3.selectionForeground = contrast($Prop.3.selectionBackground,#000,#fff)
Prop.4.selectionBackground = #0f0
Prop.4.selectionForeground = contrast($Prop.4.selectionBackground,#000,#fff)
Prop.5.selectionBackground = #00f
Prop.5.selectionForeground = contrast($Prop.5.selectionBackground,#000,#fff)
Prop.6.selectionBackground = #FFCC00
Prop.6.selectionForeground = contrast($Prop.6.selectionBackground,#000,#fff)
Prop.7.selectionBackground = #FF9500
Prop.7.selectionForeground = contrast($Prop.7.selectionBackground,#000,#fff)