Color modes

There are a few themes which can be adjusted to change the output color mode.

Night

Day and night themes in Android

AppCompat has a new theme called DayNight since Support Lib 23.2.0. So, if your activity's theme extends from one of the DayNight variants then you can switch between dark theme and light theme in your activity as follows.

Java

int mode = isNight ? AppCompatDelegate.MODE_NIGHT_YES : AppCompatDelegate.MODE_NIGHT_NO;
getDelegate().setLocalNightMode(mode);
recreate();

Kotlin

val mode = if (isNight) AppCompatDelegate.MODE_NIGHT_YES else AppCompatDelegate.MODE_NIGHT_NO
delegate.setLocalNightMode(mode)
recreate()

As you can see, to take any effect for changing night mode the activity should be re-created.

For example, in our DocumentActivity, we change the device UI night mode when the PDFViewCtrl's color mode is updated:

Java

@Override
public boolean onColorModeUpdated() {
    boolean isDarkMode = PdfViewCtrlSettingsManager.isDarkMode(this);
        if (isDeviceNightMode() != isDarkMode) {
            getDelegate().setLocalNightMode(isDarkMode
                ? AppCompatDelegate.MODE_NIGHT_YES
                : AppCompatDelegate.MODE_NIGHT_NO);
        recreate();
        return true;
    }
    return false;
}

public boolean isDeviceNightMode() {
    int currentNightMode = getResources().getConfiguration().uiMode
        & Configuration.UI_MODE_NIGHT_MASK;
    return currentNightMode == Configuration.UI_MODE_NIGHT_YES;
}

Kotlin

fun onColorModeUpdated(): Boolean {
    val isDarkMode = PdfViewCtrlSettingsManager.isDarkMode(this)
    if (isDeviceNightMode() != isDarkMode) {
        delegate.setLocalNightMode(if (isDarkMode)
            AppCompatDelegate.MODE_NIGHT_YES
        else
            AppCompatDelegate.MODE_NIGHT_NO)
        recreate()
        return true
    }
    return false
}

fun isDeviceNightMode(): Boolean {
    val currentNightMode = resources.configuration.uiMode and Configuration.UI_MODE_NIGHT_MASK
    return currentNightMode == Configuration.UI_MODE_NIGHT_YES
}

You can also have different styles for device day/night modes by creating new resources for night. This involves adding a new directory to the resources folder, using the night qualifier, to re-define the resources. In the following example, primary colors and accent color are different in day and night mode:

res/values/styles.xml

<style name="PDFTronAppTheme" parent="PDFTronAppThemeBase"> <item name="colorPrimary">@color/color_primary_day</item> <item name="colorPrimaryDark">@color/color_primary_dark_day</item> <item name="colorAccent">@color/color_accent_day</item> </style>

res/values-night/styles.xml

<style name="PDFTronAppTheme" parent="PDFTronAppThemeBase"> <item name="colorPrimary">@color/color_primary_night</item> <item name="colorPrimaryDark">@color/color_primary_dark_night</item> <item name="colorAccent">@color/color_accent_night</item> </style>

Custom

Page color mode

PDFViewCtrl has three special color modes: night mode, inverted color mode, and custom color mode. In night mode, colors are adjusted to improve reading at night, in inverted color mode, all colors are inverted, and in custom color mode, you can set a custom color for text and the background color.

Color modes from left to right: normal color mode, inverted color mode, night mode and custom color mode.

Set the color mode

To set the color mode:

1. Find the constant value of the color mode

Color mode	Constant value
Normal color mode	PDFRasterizer.e_postprocess_none
Night mode	PDFRasterizer.e_postprocess_night_mode
Inverted color mode	PDFRasterizer.e_postprocess_invert
Custom color mode	PDFRasterizer.e_postprocess_gradient_map

1. Call setColorPostProcessMode(int).
2. Optionally, set the PDFViewCtrl background color for the best visual result. You can set background color by calling [setClientBackgroundColor(int, int, int, boolean)](https://sdk.apryse.com/api/android/javadoc/reference/com/pdftron/pdf/PDFViewCtrl.html#setClientBackgroundColor(int, int, int, boolean)).For example, set the background color to black for night mode:

Java

mPdfViewCtrl.setClientBackgroundColor(0, 0, 0, false);

Kotlin

mPdfViewCtrl.setClientBackgroundColor(0, 0, 0, false)

1. If you are using postprocess_gradient_map, call [PDFViewCtrl.setColorPostProcessColors(int, int)](https://sdk.apryse.com/api/android/javadoc/reference/com/pdftron/pdf/PDFViewCtrl.html#setColorPostProcessColors(int, int)) to set the white and black points. For example, for a sepia effect, try:

Java

int darkBrown = Color.rgb(61, 38, 10);
int lightBrown = Color.rgb(245, 224, 202);
mPdfViewCtrl.setColorPostProcessColors(lightBrown, darkBrown);

Kotlin

val darkBrown = Color.rgb(61, 38, 10)
val lightBrown = Color.rgb(245, 224, 202)
mPdfViewCtrl.setColorPostProcessColors(lightBrown, darkBrown)

1. Update PDFViewCtrl to redraw the contents:Sample result when using postprocess_gradient_map and a light/dark brown for the white/black color: The example below shows all of this functionality being used to set up a custom color mode for PDFViewCtrl:Result:

Java

mPdfViewCtrl.update(true);

Kotlin

mPdfViewCtrl.update(true)

Java

private PDFViewCtrl mPdfViewCtrl;
// ...
// Sets background color to dark gray, as well as text color to red.
private void setCustomColorMode(@ColorInt int backgroundColor, @ColorInt int textColor) throws PDFNetException {
    // Sets color process mode
    mPdfViewCtrl.setColorPostProcessMode(PDFRasterizer.e_postprocess_gradient_map);
    // Sets client area color to backgroundColor
    mPdfViewCtrl.setClientBackgroundColor(Color.red(backgroundColor), Color.green(backgroundColor), Color.blue(backgroundColor), false);
    // Sets background color and text color
    mPdfViewCtrl.setColorPostProcessColors(backgroundColor, textColor);
    // Updates mPdfViewCtrl
    mPdfViewCtrl.update(true);
}

Kotlin

private var mPdfViewCtrl: PDFViewCtrl? = null
// ...
// Sets background color to dark gray, as well as text color to red.
@Throws(PDFNetException::class)
private fun setCustomColorMode(@ColorInt backgroundColor: Int, @ColorInt textColor: Int) {
    // Sets color process mode
    mPdfViewCtrl!!.colorPostProcessMode = PDFRasterizer.e_postprocess_gradient_map
    // Sets client area color to backgroundColor
    mPdfViewCtrl!!.setClientBackgroundColor(Color.red(backgroundColor), Color.green(backgroundColor), Color.blue(backgroundColor), false)
    // Sets background color and text color
    mPdfViewCtrl!!.setColorPostProcessColors(backgroundColor, textColor)
    // Updates mPdfViewCtrl
    mPdfViewCtrl!!.update(true)
}

Alternatively, you can also set custom color mode by adding a gradient map image as follows:

1. Add a gradient map .png image to your project res/raw folder.For example, add the following image to res/raw folder and name it custom_mode_filter.png:

To learn more about res/raw resource directory, see Providing Resources

1. Set the gradient image to a new MappedFile:

Java

InputStream is = null;
OutputStream os = null;
MappedFile mappedFile = null;
try {
    File filterFile = new File(activity.getCacheDir(), "cachedCustomColorFilter.png");
    if (!filterFile.exists() || !filterFile.isFile()) {
        is = getResources().openRawResource(R.raw.custom_mode_filter);
        os = new FileOutputStream(filterFile);
        IOUtils.copy(is, os);
    }
    mappedFile = new MappedFile(filterFile.getAbsolutePath());
} catch (Exception e) {
    e.printStackTrace();
} finally {
    IOUtils.closeQuietly(is);
    IOUtils.closeQuietly(os);
}

Kotlin

var inputStream: InputStream? = null
var outputStream: OutputStream? = null
var mappedFile: MappedFile? = null
try {
    val filterFile = File(activity.getCacheDir(), "cachedCustomColorFilter.png")
    if (!filterFile.exists() || !filterFile.isFile) {
        inputStream = resources.openRawResource(R.raw.custom_mode_filter)
        outputStream = FileOutputStream(filterFile)
        IOUtils.copy(inputStream, outputStream)
    }
    mappedFile = MappedFile(filterFile.absolutePath)
} catch (e: Exception) {
    e.printStackTrace()
} finally {
    IOUtils.closeQuietly(inputStream)
    IOUtils.closeQuietly(outputStream)
}

1. Set the mappedFile created above to PDFViewCtrl by calling PDFViewCtrl.setColorPostProcessMapFile(Filter).Where pdfViewCtrl is an instance of PDFViewCtrl.

Java

if (mappedFile != null) {
    try {
        pdfViewCtrl.setColorPostProcessMapFile(mappedFile);
    } catch (PDFNetException e) {
        e.printStackTrace();
    }
}

Kotlin

if (mappedFile != null) {
    try {
        pdfViewCtrl!!.setColorPostProcessMapFile(mappedFile)
    } catch (e: PDFNetException) {
        e.printStackTrace()
    }
}

1. Set the color process mode PDFRasterizer.e_postprocess_gradient_map to pdfViewCtrl by calling pdfViewCtrl.setColorPostProcessMode(int). Then update pdfViewCtrl:

Java

try {
    pdfViewCtrl.setColorPostProcessMode(PDFRasterizer.e_postprocess_gradient_map);
    // Sets client area background color to rgb(138, 138, 138)
    pdfViewCtrl.setClientBackgroundColor(138, 138, 138, false);
    // Updates pdfViewCtrl
    pdfViewCtrl.update(true);
} catch (PDFNetException e) {
    e.printStackTrace();
}

Kotlin

try {
  pdfViewCtrl.colorPostProcessMode = PDFRasterizer.e_postprocess_gradient_map
  // Sets client area background color to rgb(138, 138, 138)
  pdfViewCtrl.setClientBackgroundColor(138, 138, 138, false)
  // Updates pdfViewCtrl
  pdfViewCtrl.update(true)
} catch (e: PDFNetException) {
  e.printStackTrace()
}

Result: