Screenshot Service: write ImageWrapper to Screenshot

frontend/resources/include/Screenshots.h

@@ -66,6 +66,18 @@ class IImageDataWriter {
     ~IImageDataWriter() = default;
 };
 
+struct ImageWrapper;
+class ImageWrapperScreenshotSource : public IScreenshotSource {
+public:
+    ImageWrapperScreenshotSource() = default;
+    ImageWrapperScreenshotSource(ImageWrapper const& image);
+
+    ScreenshotImageData const& take_screenshot() const override;
+
+private:
+    ImageWrapper* m_image = nullptr;
+};
+
 class GLScreenshotSource : public IScreenshotSource {
 public:
     enum ReadBuffer { FRONT, BACK, COLOR_ATT0, COLOR_ATT1, COLOR_ATT2, COLOR_ATT3};

frontend/services/screenshot_service/Screenshot_Service.cpp

@@ -11,6 +11,9 @@
 #include <glad/glad.h>
 #include "GUIState.h"
 
+#include "ImageWrapper.h"
+#include "ImageWrapper_to_ByteArray.h"
+
 #include "mmcore/MegaMolGraph.h"
 
 // to write png files
@@ -109,6 +112,35 @@ static bool write_png_to_file(megamol::frontend_resources::ScreenshotImageData c
     return true;
 }
 
+megamol::frontend_resources::ImageWrapperScreenshotSource::ImageWrapperScreenshotSource(ImageWrapper const& image)
+    : m_image{& const_cast<ImageWrapper&>(image)}
+{}
+
+megamol::frontend_resources::ScreenshotImageData const& megamol::frontend_resources::ImageWrapperScreenshotSource::take_screenshot() const {
+    static ScreenshotImageData screenshot_image;
+
+    // keep allocated vector memory around
+    // note that this initially holds a nullptr texture - bad!
+    static frontend_resources::byte_texture image_bytes({});
+
+    // fill bytes with image data
+    image_bytes = *m_image;
+    auto& byte_vector = image_bytes.as_byte_vector();
+
+    screenshot_image.resize(m_image->size.width, m_image->size.height);
+
+    for (size_t i = 0, j = 0; i < byte_vector.size();) {
+        auto r = [&]() { return byte_vector[i++]; };
+        auto g = [&]() { return byte_vector[i++]; };
+        auto b = [&]() { return byte_vector[i++]; };
+        auto a = [&]() { return (m_image->channels == ImageWrapper::DataChannels::RGBA8) ? byte_vector[i++] : default_alpha_value; }; // alpha either from image or 1.0
+        ScreenshotImageData::Pixel pixel = { r(), g(), b(), a() };
+        screenshot_image.image[j++] = pixel;
+    }
+
+    return screenshot_image;
+}
+
 void megamol::frontend_resources::GLScreenshotSource::set_read_buffer(ReadBuffer buffer) {
     m_read_buffer = buffer;
     GLenum read_buffer;
@@ -190,6 +222,12 @@ bool Screenshot_Service::init(const Config& config) {
         return m_toFileWriter_resource.write_screenshot(m_frontbufferSource_resource, filename);
     };
 
+    this->m_imagewrapperToPNG_trigger = [&](megamol::frontend_resources::ImageWrapper const& image, std::string const& filename) -> bool
+    {
+        log("write screenshot to " + filename);
+        return m_toFileWriter_resource.write_screenshot(megamol::frontend_resources::ImageWrapperScreenshotSource(image), filename);
+    };
+
     log("initialized successfully");
     return true;
 }
@@ -205,7 +243,8 @@ std::vector<FrontendResource>& Screenshot_Service::getProvidedResources() {
     {
         {"GLScreenshotSource", m_frontbufferSource_resource},
         {"ImageDataToPNGWriter", m_toFileWriter_resource},
-        {"GLFrontbufferToPNG_ScreenshotTrigger", m_frontbufferToPNG_trigger}
+        {"GLFrontbufferToPNG_ScreenshotTrigger", m_frontbufferToPNG_trigger},
+        {"ImageWrapperToPNG_ScreenshotTrigger", m_imagewrapperToPNG_trigger}
     };
 
     return m_providedResourceReferences;

frontend/services/screenshot_service/Screenshot_Service.hpp

@@ -58,6 +58,7 @@ class Screenshot_Service final : public AbstractFrontendService {
     megamol::frontend_resources::ScreenshotImageDataToPNGWriter m_toFileWriter_resource;
 
     std::function<bool(std::string const&)> m_frontbufferToPNG_trigger;
+    std::function<bool(megamol::frontend_resources::ImageWrapper const&, std::string const&)> m_imagewrapperToPNG_trigger;
 
     std::vector<FrontendResource> m_providedResourceReferences;
     std::vector<std::string> m_requestedResourcesNames;