ImageReader.cpp

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// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
// Require ImageMagick support
#ifdef USE_IMAGEMAGICK
 
#include "MagickUtilities.h"
#include "QtUtilities.h"
 
#include "ImageReader.h"
#include "Exceptions.h"
#include "Frame.h"
 
using namespace openshot;
 
ImageReader::ImageReader(const std::string& path, bool inspect_reader) : path(path), is_open(false)
{
    // Open and Close the reader, to populate its attributes (such as height, width, etc...)
    if (inspect_reader) {
        Open();
        Close();
    }
}
 
// Open image file
void ImageReader::Open()
{
    // Open reader if not already open
    if (!is_open)
    {
        // Attempt to open file
        try
        {
            // load image
            image = std::make_shared<Magick::Image>(path);
 
            // Give image a transparent background color
            image->backgroundColor(Magick::Color("none"));
            MAGICK_IMAGE_ALPHA(image, true);
        }
        catch (const Magick::Exception& e) {
            // raise exception
            throw InvalidFile("File could not be opened.", path);
        }
 
        // Update image properties
        info.has_audio = false;
        info.has_video = true;
        info.has_single_image = true;
        info.file_size = image->fileSize();
        info.vcodec = image->format();
        info.width = image->size().width();
        info.height = image->size().height();
        info.pixel_ratio = openshot::Fraction(1, 1);
        info.fps = openshot::Fraction(30, 1);
        info.video_timebase = info.fps.Reciprocal();
        // Default still-image duration: 1 hour, aligned to fps
        info.video_length = 60 * 60 * info.fps.num; // 3600 seconds * 30 fps
        info.duration = static_cast<float>(info.video_length / info.fps.ToDouble());
 
        // Calculate the DAR (display aspect ratio)
        Fraction dar(
            info.width * info.pixel_ratio.num,
            info.height * info.pixel_ratio.den);
 
        // Reduce DAR fraction & set ratio
        dar.Reduce();
        info.display_ratio = dar;
 
        // Mark as "open"
        is_open = true;
    }
}
 
void ImageReader::Close()
{
    if (is_open)
    {
        is_open = false;
        // Delete the image
        image.reset();
    }
}
 
// Get an openshot::Frame object for a specific frame number of this reader.
std::shared_ptr<Frame> ImageReader::GetFrame(int64_t requested_frame)
{
    if (!is_open) {
        throw ReaderClosed(
            "The ImageReader is closed. "
            "Call Open() before calling this method.", path);
    }
 
    // Create or get frame object
    auto image_frame = std::make_shared<Frame>(
        requested_frame,
        image->size().width(), image->size().height(),
        "#000000", 0, 2);
 
    // Add Image data to frame
    auto qimage = openshot::Magick2QImage(image);
    image_frame->AddImage(qimage);
    return image_frame;
}
 
// Generate JSON string of this object
std::string ImageReader::Json() const {
 
    // Return formatted string
    return JsonValue().toStyledString();
}
 
// Generate Json::Value for this object
Json::Value ImageReader::JsonValue() const {
 
    // get parent properties
    Json::Value root = ReaderBase::JsonValue();
 
    root["type"] = "ImageReader";
    root["path"] = path;
    return root;
}
 
// Load JSON string into this object
void ImageReader::SetJson(const std::string value) {
 
    // Parse JSON string into JSON objects
    try
    {
        const Json::Value root = openshot::stringToJson(value);
        // Set all values that match
        SetJsonValue(root);
    }
    catch (const std::exception& e)
    {
        throw InvalidJSON(
            "JSON is invalid (missing keys or invalid data types)");
    }
}
 
// Load Json::Value into this object
void ImageReader::SetJsonValue(const Json::Value root) {
 
    // Set parent data
    ReaderBase::SetJsonValue(root);
 
    // Set data from Json (if key is found)
    if (!root["path"].isNull())
        path = root["path"].asString();
 
    if (is_open) {
        Close();
        Open();
    }
}
 
#endif //USE_IMAGEMAGICK