Mobile devices have long become a universal platform for reading, replacing paper books and specialized readers. However, standard system file viewers often cannot cope with the variety of text formats, offering only basic functionality without the ability to fine-tune. In this context, Cool Reader stands out as one of the most advanced solutions for the Android operating system, combining lightness, open source code and powerful customization tools.
This open source project does not require complex registrations, is not overloaded with advertising (in the basic version) and allows the user to adapt the interface to any visual preferences. For specialists in setting up Android gadgets The principle of operation of this application is well known, which is based on an engine capable of correctly displaying complex layout elements. Unlike many modern “heavy” aggregators, this software works stably even on older smartphone models, consuming a minimum of RAM.
Next we will analyze in detail the installation process, initial configuration and advanced settings that will turn your smartphone into an ideal e-reader. You'll learn how to set up font smoothing, create your own backlight profiles for reading in the dark, and automate the library replenishment process.
Installing the application and initial scanning of libraries
The installation process begins with downloading the installation package .apk from the official Google Play store or a trusted repository such as F-Droid. After the download is complete, the system will prompt you to open the file, and the installation wizard will automatically deploy the necessary components in the directory /data/app. It is important to note that the first time you launch the application, it will ask for permission to access the device storage.
Without granting read permissions to the internal memory or SD card, the app will not be able to detect your books. The system will prompt you to select folders to scan by default, but you can manually add any directories through the settings menu. This is especially convenient if your collection is scattered across different directories or stored on an external drive.
After you confirm permissions, the background indexing process will start. The application engine analyzes file metadata, extracting titles, authors and covers to create a beautiful catalog. If you have thousands of books in your collection, the initial scan may take several minutes, so be patient.
If you have a large library (more than 1,000 files), disable automatic scanning on every launch in the settings to speed up the opening of the application. Update the catalog manually only when adding new books.
It is worth considering that the interface and location of some menu items may vary slightly depending on the version of Android and the specific firmware build of your smartphone. Device manufacturers often modify system permission dialogs, so the path to privacy settings may vary.
Setting up text display and typography
The main advantage that gives Cool Reader ahead of competitors is a detailed setting of text rendering. By going to the menu Settings → View → Font, you get access to choosing a typeface, size, line spacing and indents. For comfortable reading on high-resolution screens, it is recommended to enable font smoothing, which makes characters clearer and more pleasing to the eye.
Particular attention should be paid to setting word hyphens. The application algorithm allows you to flexibly manage hyphenation rules, eliminating dangling lines and ugly paragraph breaks. This is critically important when reading fiction, where maintaining the author's rhythm and structure of the text plays a key role.
The user can create several display profiles for different genres. For example, for technical documentation with tables and code, a monospaced font and large margins are suitable, and for novels, a classic serif with a dense typesetting is suitable. Switching between profiles is carried out in a couple of touches through the pop-up menu.
☑️ Optimal font settings for screen reading
⚠️ Attention: Using too small fonts (less than 10 sp) on AMOLED screens can lead to a flickering effect of subpixels when scrolling, which causes rapid visual fatigue.
By experimenting with the parameters, you can achieve picture quality comparable to a paper edition. Do not forget that optimal values are individual and depend on your visual acuity and the diagonal of the device screen.
Working with file formats and encodings
The application engine supports a wide range of text formats, making it a universal tool for any library. Among the most popular formats are FB2, EPUB, MOBI, TXT, HTML and RTF. Each of them is processed by a special module that ensures the correct display of specific elements, such as footnotes, tables of contents and illustrations.
One of the common problems when reading old text files is incorrect encoding. If instead of Russian text you see a set of incomprehensible characters, you must manually specify the encoding in the file settings. The application allows you to choose from a list of popular encodings, such as UTF-8, Windows-1251 or KOI8-R.
For formats that support styles, such as EPUB and FB2, you can enable or disable the use of built-in author styles. Sometimes publishers use bad color schemes or fonts, and in such cases, forcing custom settings looks much better.
| Format | Style support | DRM support | Recommendation |
|---|---|---|---|
| FB2 | Full | No | Ideal for Russian literature |
| EPUB | Full | Partly | International standard |
| MOBI | Limited | Yes (Kindle) | For old Amazon books |
| TXT | No | No | Plain text only |
It is worth noting that that support for DRM (Digital Rights Management) protected files is limited. The application is not intended to crack security, so books purchased in closed ecosystems with strict linking to an account may not open without first converting.
Library organization and navigation
Managing a large collection of books requires a convenient navigation system. In the library view settings, you can choose to display it as a list, tile, or detailed table with covers. Sorting is available by file name, book title, author, date added, or last read time.
The Unread feature allows you to quickly filter out books you haven't started or finished yet. Reading status is tracked automatically: as soon as you open a file and scroll through it, it is marked as read or currently being read.
For lovers of serial literature, the ability to group books by series has been implemented. If the file's metadata is filled out correctly, the application will automatically collect all volumes of one saga into a single folder, which eliminates the need to search for a sequel manually.
How to correct incorrect metadata?
If a book is displayed with the wrong title or author, click on it and hold your finger until the context menu appears. Select "Properties" or "Edit", where you can manually enter the correct data. These changes will be saved in the application database, but not in the file itself.
Library search works instantly even if there are tens of thousands of files. It is enough to enter a few letters of the author's last name or title, and the system will return relevant results, ignoring the case of characters.
Setting night mode and color schemes
Reading in low light conditions requires a special approach to setting up the screen so as not to strain your eyesight. In the section Settings → Colors a selection of preset schemes is available, including the classic "Black on White", "Sepia" to simulate old paper and "Night mode".
Night mode in Cool Reader is implemented not just as inversion of colors, but as a thoughtful scheme with a dark gray background and light gray text. This reduces contrast to a comfortable level, eliminating the flashlight effect in the user's face.
Advanced users can create their own color scheme by setting precise RGB values for background, text, headings and links. This allows you to achieve the ideal combination of colors for the specific matrix of your display.
⚠️ Attention: When using a completely black background (#000000) on OLED screens, a black smearing effect may occur when quickly scrolling text due to slow pixel response. It is recommended to use a dark gray tint (#121212 or #1a1a1a).
You can also adjust the backlight brightness directly within the application, regardless of the Android system settings. The brightness slider is usually activated by swiping up or down the screen while reading.
Using a warm color temperature (shift to the yellow spectrum) in the evening reduces melatonin production and helps you fall asleep faster after reading.
Control gestures and hotkeys
For maximum one-handed reading comfort The developers have implemented a flexible gesture system. By default, tapping in the center of the screen brings up the menu, tapping on the right edge scrolls the page forward, and tapping on the left edge scrolls back. However, these actions can be reassigned in the menu Settings → Control.
Volume control is supported: pressing the physical volume control buttons can be used to turn pages. This is especially convenient when the phone is lying on a table or held in an awkward position.
Additionally, you can customize the action when swiping up or down. For example, swiping up can open the table of contents, and swiping down can change the brightness. This customization allows you to customize the application to the individual habits of each user.
Some functions are hidden in the context menu, called by a long tap. There you can quickly change the font, add a bookmark, or go to a specific page by number.
Progress synchronization and backup
Although the application is positioned as a local reader, the ability to save reading progress is critical. Cool Reader stores information about the last opened page in its internal cache. If you uninstall an app, this data may be lost unless backed up.
You can use third-party cloud storage to sync your progress across multiple devices (such as a phone and tablet). The progress database file is usually located in a folder /sdcard/CoolReader/cr3.ini or in a hidden system directory of the application.
Regular backup of settings and reading progress will protect you from data loss when resetting your phone to factory settings or when switching to a new device. Simply copy the configuration files to the cloud.
Use automatic folder synchronization applications (such as Syncthing or FolderSync) so that the cr3.ini progress file is automatically updated on all your devices in real time.
Remember that manually editing configuration files is possible, but requires caution. Always make a copy of the original file before making any changes in a text editor.
Frequently asked questions (FAQ)
Why does the application not see my books in the Download folder?
Modern versions of Android (starting from 11 and higher) have strict restrictions on access to the file system (Scoped Storage). You need to give the application permission to manage all files in the system settings: Settings → Applications → Cool Reader → Permissions → All files. Also check whether the Download folder is added to the list of scanned directories in the settings of the reader itself.
How to remove ads in the free version?
The basic version of Cool Reader is completely free and It's open-source, so it doesn't have built-in advertising. If you see banner ads, you may have downloaded a fake or modified version from an unreliable source. It is recommended to delete this version and download the application exclusively from Google Play or the official project website.
Is it possible to listen to books out loud using this application?
Yes, the application supports speech synthesis (TTS). To do this, you must have a speech recognition engine installed on your device (for example, Google Text-to-Speech). Activate the feature in the reading menu by clicking on the speaker icon or selecting "Read aloud" in the settings. Speed and voice are regulated by Android system settings.
How can I restore the default settings if I mess everything up?
In the application settings menu there is a "Reset settings" or "Factory settings" button. Clicking this button will return all font, color and gesture settings to their original state. The reading progress and the list of books will be saved, since they are stored in a separate database file.
Does the application support reading books from ZIP archives?
Yes, one of the unique features of the engine is the ability to open books packed in ZIP archives without the need to first unpack them. You can add an entire archive with a series of books to the library, and the application will treat it as a folder, allowing you to switch between files within the archive.