Architecture

Overview

package lib { component util as lib_util component threadpool as lib_threadpool component memory_manager as lib_memory_manager component plugin_interfaces as lib_plugin_interfaces component scroom as lib_scroom_lib component tiledbitmap as lib_tiledbitmap component ruler as lib_ruler } component scroom lib_plugin_interfaces --> lib_util lib_scroom_lib --> lib_plugin_interfaces lib_threadpool --> lib_util lib_memory_manager --> lib_threadpool lib_memory_manager --> lib_util lib_tiledbitmap --> lib_memory_manager lib_tiledbitmap --> lib_plugin_interfaces lib_tiledbitmap --> lib_scroom_lib lib_tiledbitmap --> lib_threadpool lib_ruler --> lib_util scroom --> lib_ruler scroom --> lib_scroom_lib scroom --> lib_tiledbitmap scroom --> lib_util

Overview of Scrooms libraries

package lib { component threadpool as lib_threadpool component plugin_interfaces as lib_plugin_interfaces component scroom as lib_scroom_lib component tiledbitmap as lib_tiledbitmap } package plugin { component colormap as plugin_spcolormap component example as plugin_spexample component measure as plugin_spmeasure component metadata as plugin_spmetadata component pipette as plugin_sppipette component tiff as plugin_sptiff component transparentoverlay as plugin_sptransparentoverlay } plugin_spcolormap --> lib_plugin_interfaces plugin_spexample --> lib_plugin_interfaces plugin_spexample --> lib_scroom_lib plugin_spmeasure --> lib_plugin_interfaces plugin_spmeasure --> lib_scroom_lib plugin_spmetadata --> lib_plugin_interfaces plugin_spmetadata --> lib_threadpool plugin_sppipette --> lib_plugin_interfaces plugin_sppipette --> lib_scroom_lib plugin_sppipette --> lib_threadpool plugin_sptiff --> lib_scroom_lib plugin_sptiff --> lib_tiledbitmap plugin_sptransparentoverlay --> lib_plugin_interfaces plugin_sptransparentoverlay --> lib_scroom_lib

Overview of Scrooms plugins

No startup or shutdown code

Some systems have dedicated code to start up and shut down the application. Not Scroom. Scroom deals with documents (more accurately presentations) that allocate huge amounts of resources. These can be opened at any time, and resources should be released as soon as the document is closed, not at shutdown. And if that happens, startup and shutdown code really has nothing to do.

Asynchronous

Scroom is largely asynchronous. We start some action, and when it finishes, that generates an event which triggers further actions, such as updating the UI. We do not explicitly wait for actions to finish (but many are cancelable), not even when closing a document or even the application.

This means that it is normal for your code to still be running on some thread, even when the document, or scroom itself, is being closed. To deal with this, classes need to keep alive everything they need to function, because otherwise things might be destroyed because the document is closed. This explains why shared pointers are used extensively.