FrescoImageViewer

Simple customizable full screen image viewer for Fresco library that includes "pinch to zoom" and "swipe to dismiss" gestures. Based on PhotoDraweeView by ongakuer.

Who we are

Need iOS and Android apps, MVP development or prototyping? Contact us via info@stfalcon.com. We develop software since 2009, and we're known experts in this field. Check out our portfolio and see more libraries from stfalcon-studio.

Requirements

Fresco v.0.12.0 and higher
SDK 14 and and higher

Demo Application

Usage

Simple usage

All you need to show a viewer is pass the context, start position and List or String[] into builder and call show().

new ImageViewer.Builder(context, list)
        .setStartPosition(startPosition)
        .show();

Custom objects

But what if in your application images are represented not only with urls? For example, you have object with url and description? You'll have to convert it to list of Strings and only then pass it to viewer, right? No, it's unnecessary! With ImageViewer.Formatter you can pass list of your custom images to viewer and simply write a rule for url extracting:

List<CustomImage> images = getImages();
new ImageViewer.Builder<>(this, images)
        .setFormatter(new ImageViewer.Formatter<CustomImage>() {
            @Override
            public String format(CustomImage customImage) {
                return customImage.getUrl();
            }
        })
        .show();

If formatter isn't passed, Object.toString() will be used for image formatting as default behavior.

Piece of cake! 🍰 😉

Reminder

Don't forget to initialize Fresco in your Application class:

Fresco.initialize(this);

And if you expect to open really large images, use configuration below for better performance:

ImagePipelineConfig config = ImagePipelineConfig.newBuilder(this)
    .setProgressiveJpegConfig(new SimpleProgressiveJpegConfig())
    .setResizeAndRotateEnabledForNetwork(true)
    .setDownsampleEnabled(true)
    .build();
Fresco.initialize(this, config);

Customizing

You can also customize a viewer to fit your needs.

Background

Use setBackgroundColorRes(colorRes) or setBackgroundColor(colorInt) to set color for fading background.

Custom overlay view

If you need some content over the image (e.g. sharing or download button, description, numeration etc.) you can set your custom view using setOverlayView(customView) and bind it with viewer through ImageViewer.OnImageChangeListener.

Custom drawee hierarchy

Of course, according to Fresco flexibility, you can use your custom GenericDraweeHierarchy. To do this you simply need to create GenericDraweeHierarchyBuilder and pass it into builder:

GenericDraweeHierarchyBuilder hierarchyBuilder = GenericDraweeHierarchyBuilder.newInstance(getResources())
        .setFailureImage(R.drawable.failureDrawable)
        .setProgressBarImage(R.drawable.progressBarDrawable)
        .setPlaceholderImage(R.drawable.placeholderDrawable);

builder.setCustomDraweeHierarchyBuilder(hierarchyBuilder)

❗But there is a limitation: default ScaleType in hierarchy is ScaleType.FIT_CENTER, so custom value will be ignored

Custom image requests

For rare cases like post-processing or bitmap resizing you need to use your custom ImageRequestBuilder. Create it with ImageViewer.createImageRequestBuilder() and after configuration pass it to viewer through setCustomImageRequestBuilder(ImageRequestBuilder).

builder.setCustomImageRequestBuilder(
            ImageViewer.createImageRequestBuilder()
                    .setPostprocessor(new GrayscalePostprocessor()));

Image margin

Simply add margins between images with dimens with setImageMargin(context, dimen) or in px using setImageMarginPx(marginPx).

Container padding

Overlay image hides part of image? Set container padding with dimens using setContainerPadding(context, start, top, end, bottom) or setContainerPadding(context, dimean) for all sides at once. For setting padding in pixels, just use setContainerPaddingPx(...) method.

Status bar visibility

To show/hide status bar in view property you can set hideStatusBar(boolean) in builder. The default value is true.

Gestures disabling

If you need to disable some of gestures - do it using allowSwipeToDismiss(boolean) and allowZooming(boolean) accordingly.

Here is an example that sets all the possible options:

new ImageViewer.Builder<>(this, images)
        .setStartPosition(startPosition)
        .hideStatusBar(false)
        .allowZooming(true)
        .allowSwipeToDismiss(true)
        .setBackgroundColorRes(colorRes)
        //.setBackgroundColor(color)
        .setImageMargin(margin)
        //.setImageMarginPx(marginPx)
        .setContainerPadding(this, dimen)
        //.setContainerPadding(this, dimenStart, dimenTop, dimenEnd, dimenBottom)
        //.setContainerPaddingPx(padding)
        //.setContainerPaddingPx(start, top, end, bottom)
        .setCustomImageRequestBuilder(imageRequestBuilder)
        .setCustomDraweeHierarchyBuilder(draweeHierarchyBuilder)
        .setImageChangeListener(imageChangeListener)
        .setOnDismissListener(onDismissListener)
        .setOverlayView(overlayView)
        .show();

With this possibilities you can achieve something like this:

You can take a look at sample project for more information.

Install

Download via Gradle:

compile 'com.github.stfalcon:frescoimageviewer:0.5.0'

or Maven:

<dependency>
  <groupId>com.github.stfalcon</groupId>
  <artifactId>frescoimageviewer</artifactId>
  <version>0.5.0</version>
  <type>pom</type>
</dependency>

Changelog

See the changelog to be aware of latest improvements and fixes.

License

Copyright (C) 2017 stfalcon.com

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

http://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.

iq5sa/FrescoImageViewer