Example usage for android.support.v4.graphics ColorUtils calculateContrast

Introduction

In this page you can find the example usage for android.support.v4.graphics ColorUtils calculateContrast.

Prototype

public static double calculateContrast(@ColorInt int foreground, @ColorInt int background) 

Source Link

Document

Returns the contrast ratio between foreground and background .

Usage

From source file:android.support.v7.app.MediaRouterThemeHelper.java

public static @ControllerColorType int getControllerColor(Context context, int style) {
    int primaryColor = getThemeColor(context, style, android.support.v7.appcompat.R.attr.colorPrimary);
    if (ColorUtils.calculateContrast(COLOR_WHITE_ON_DARK_BACKGROUND, primaryColor) >= MIN_CONTRAST) {
        return COLOR_WHITE_ON_DARK_BACKGROUND;
    }/*from ww  w  .j  av a 2 s. co  m*/
    return COLOR_DARK_ON_LIGHT_BACKGROUND;
}

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From source file:android.support.v7.app.MediaRouterThemeHelper.java

public static int getButtonTextColor(Context context) {
    int primaryColor = getThemeColor(context, 0, android.support.v7.appcompat.R.attr.colorPrimary);
    int backgroundColor = getThemeColor(context, 0, android.R.attr.colorBackground);

    if (ColorUtils.calculateContrast(primaryColor, backgroundColor) < MIN_CONTRAST) {
        // Default to colorAccent if the contrast ratio is low.
        return getThemeColor(context, 0, android.support.v7.appcompat.R.attr.colorAccent);
    }/*from  w  ww .  ja va2  s .  co m*/
    return primaryColor;
}

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From source file:com.android.launcher3.dynamicui.ExtractionUtils.java

/** @return Whether the foreground color is legible on the background color. */
private static boolean isLegible(int foreground, int background) {
    background = ColorUtils.setAlphaComponent(background, 255);
    return ColorUtils.calculateContrast(foreground, background) >= MIN_CONTRAST_RATIO;
}

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From source file:org.voidsink.anewjkuapp.fragment.CalendarFragment2.java

@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
    ArrayList<WeekViewEvent> events = mWeekViewLoader.getEvents(loader.getId());
    events.clear();/*www  .j a  v a  2 s. co m*/

    Account mAccount = AppUtils.getAccount(getContext());
    if (mAccount != null) {
        // fetch calendar colors
        final SparseIntArray mColors = new SparseIntArray();
        ContentResolver cr = getContext().getContentResolver();
        Cursor cursor = cr.query(CalendarContractWrapper.Calendars.CONTENT_URI(), new String[] {
                CalendarContractWrapper.Calendars._ID(), CalendarContractWrapper.Calendars.CALENDAR_COLOR() },
                null, null, null);
        if (cursor != null) {
            while (cursor.moveToNext()) {
                int color = cursor.getInt(1);

                double lastContrast = ColorUtils.calculateContrast(color, mWeekView.getEventTextColor());
                //Log.d(TAG, String.format("color=%d %d %d, contrast=%f", Color.red(color), Color.green(color), Color.blue(color), lastContrast));

                while (lastContrast < 1.6) {
                    float[] hsv = new float[3];

                    Color.colorToHSV(color, hsv);
                    hsv[2] = Math.max(0f, hsv[2] - 0.033f); // darken
                    color = Color.HSVToColor(hsv);

                    lastContrast = ColorUtils.calculateContrast(color, mWeekView.getEventTextColor());
                    //Log.d(TAG, String.format("new color=%d %d %d, contrast=%f", Color.red(color), Color.green(color), Color.blue(color), lastContrast));

                    if (hsv[2] == 0)
                        break;
                }

                mColors.put(cursor.getInt(0), color);
            }
            cursor.close();
        }

        if (data != null) {
            data.moveToFirst();
            data.moveToPrevious();
            while (data.moveToNext()) {

                boolean allDay = data.getInt(CalendarUtils.COLUMN_EVENT_ALL_DAY) == 1;

                Calendar startTime = Calendar.getInstance();
                if (allDay) {
                    startTime.setTimeZone(TimeZone.getTimeZone("UTC"));
                }
                startTime.setTimeInMillis(data.getLong(CalendarUtils.COLUMN_EVENT_DTSTART));

                Calendar endTime = Calendar.getInstance();
                if (allDay) {
                    endTime.setTimeZone(TimeZone.getTimeZone("UTC"));
                }
                endTime.setTimeInMillis(data.getLong(CalendarUtils.COLUMN_EVENT_DTEND));
                if (allDay && endTime.getTimeInMillis() % DateUtils.DAY_IN_MILLIS == 0) {
                    endTime.add(Calendar.MILLISECOND, -1);
                }

                WeekViewEvent event = new WeekViewEvent(data.getLong(CalendarUtils.COLUMN_EVENT_ID),
                        data.getString(CalendarUtils.COLUMN_EVENT_TITLE),
                        data.getString(CalendarUtils.COLUMN_EVENT_LOCATION), startTime, endTime, allDay);

                event.setColor(mColors.get(data.getInt(CalendarUtils.COLUMN_EVENT_CAL_ID)));

                events.add(event);
            }
        }
    }

    mWeekView.notifyDatasetChanged();
}

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