Sequencer - Some work towards having a zoomable thing

Display areas for the header and the sequencer itself; writes lewd text
in the header with the appropriate font; computes some of the data for
proper zooming, and prints it to stdout because fuck you, that's why.

main.cc

@@ -76,6 +76,10 @@ void T_Main::mainLoop( )
 		if ( needInit ) {
 			initDemo( );
 		}
+#warning FIXME remove this
+		if ( !sequencer ) {
+			sequencer.setNew( );
+		}
 
 		Globals::Watcher( ).check( );
 		Globals::Shaders( ).update( );

sync.hh

@@ -289,6 +289,11 @@ struct T_SyncManager : public virtual A_MouseCtrl
 	float duration( ) const noexcept
 		{ return time_.duration( ); }
 
+	uint32_t durationUnits( ) const noexcept
+		{ return time_.iDuration; }
+	float durationUnitSize( ) const noexcept
+		{ return time_.uDuration; }
+
 	void setTime( const float time );
 	void timeDelta( const float delta )
 		{ setTime( time_.time + delta ); }

syncview.cc

@@ -1,6 +1,10 @@
 #include "externals.hh"
 #include "syncview.hh"
 #include "globals.hh"
+#include "window.hh"
+
+#define IMGUI_DEFINE_MATH_OPERATORS
+#include <imgui_internal.h>
 
 using namespace ebcl;
 
@@ -10,7 +14,19 @@ namespace {
 
 struct T_SyncViewImpl_
 {
+	static constexpr float SeqHeaderHeight = 24;
+	static constexpr float MinUnitWidth = 80;
+
+	const uint32_t ColFrame{ ImGui::GetColorU32( ImVec4{ 0 , 0 , 0 , .8 } ) };
+	const uint32_t ColHeader{ ImGui::GetColorU32( ImVec4{ .5 , .5 , .5 , .8 } ) };
+	const uint32_t ColHeaderText{ ImGui::GetColorU32( ImVec4{ 0 , 0 , 0 , 1 } ) };
+	const uint32_t ColMain{ ImGui::GetColorU32( ImVec4{ .4 , .4 , .4 , .8 } ) };
+
+	float zoomLevel{ 1.f };
+
 	bool display( ) noexcept;
+	void sequencerWidget( ) noexcept;
+	void sequencerHeader( ImRect const& bb ) noexcept;
 };
 
 
@@ -24,8 +40,10 @@ bool T_SyncViewImpl_::display( ) noexcept
 	SetNextWindowSize( ImVec2( dspSize.x , 150 ) , ImGuiSetCond_Appearing );
 	SetNextWindowPos( ImVec2( 0 , dspSize.y - 150 ) , ImGuiSetCond_Appearing );
 	bool displayed{ true };
-	Begin( "Sequencer" , &displayed , ImGuiWindowFlags_NoCollapse );
+	Begin( "Sequencer" , &displayed , ImGuiWindowFlags_NoCollapse
+				| ImGuiWindowFlags_NoScrollWithMouse );
 	if ( !displayed ) {
+		End( );
 		return false;
 	}
 
@@ -46,11 +64,98 @@ bool T_SyncViewImpl_::display( ) noexcept
 	}
 	PopItemWidth( );
 	PopID( );
-	End( );
 
+	PushItemWidth( -1 );
+	sequencerWidget( );
+	PopItemWidth( );
+
+	End( );
 	return true;
 }
 
+void T_SyncViewImpl_::sequencerWidget( ) noexcept
+{
+	using namespace ImGui;
+
+	const auto width{ CalcItemWidth( ) };
+	auto* const win( GetCurrentWindow( ) );
+	const auto seqId{ win->GetID( "##sequencer" ) };
+
+	const ImVec2 cPos( win->DC.CursorPos );
+	const ImVec2 ws( GetWindowContentRegionMax( ) );
+
+	auto& style( ImGui::GetStyle( ) );
+	const ImRect bbHeader{ cPos , cPos + ImVec2( width , SeqHeaderHeight ) };
+	const ImRect bbDisplay{ ImVec2{ cPos.x , bbHeader.Max.y } ,
+		ImVec2{ cPos.x + width , GetWindowPos( ).y + ws.y - style.FramePadding.y } };
+	const ImRect bbAll{ bbHeader.Min , bbDisplay.Max };
+
+	ItemSize( bbAll , style.FramePadding.y );
+	if ( !ItemAdd( bbAll , seqId ) ) {
+		return;
+	}
+
+	/*
+	 * Scaling:
+	 *	At minimal zoom level, we want the whole "track" to fit inside the
+	 *		available width.
+	 *	At maximal zoom level, we want units from the sync manager to cover
+	 *		$MIN_UNIT_WIDTH pixels (that should depend on the text size).
+	 *	The displayed size of the units increases along with the zoom level.
+	 *		Display units are rescaled when the distance between them
+	 *		becomes >= 2 * $MIN_UNIT_WIDTH
+	 *	At worst, the sequence is only one unit long; this means that no
+	 *	scaling occurs between minimal and maximal levels.
+	 */
+
+	auto& sync( Globals::Sync( ) );
+	const uint32_t units{ sync.durationUnits( ) };
+	const float maxZoomUnits{ width / MinUnitWidth };
+	const float slope{ maxZoomUnits - units };
+	const float dUnits{ units + zoomLevel * slope };
+printf( "%d units ; %f/screen at max zoom ; slope %f ; display %f units at ZL %f\n" , units , maxZoomUnits , slope , dUnits , zoomLevel );
+
+	PushID( seqId );
+	BeginGroup( );
+
+	const auto hdrId{ win->GetID( "##header" ) };
+	const auto dspId{ win->GetID( "##display" ) };
+	auto* const dl( GetWindowDrawList( ) );
+
+	if ( ItemAdd( bbHeader , hdrId ) ) {
+		PushID( hdrId );
+		sequencerHeader( bbHeader );
+		PopID( );
+	}
+	if ( bbDisplay.Min.y < bbDisplay.Max.y && ItemAdd( bbDisplay , dspId ) ) {
+		// XXX display main area
+		dl->AddRectFilled( bbDisplay.Min , bbDisplay.Max ,
+				ImGui::GetColorU32( ImVec4( .4 , .4 , .4 , .8 ) ) );
+	}
+
+	EndGroup( );
+	PopID( );
+}
+
+void T_SyncViewImpl_::sequencerHeader(
+		ImRect const& bb ) noexcept
+{
+	using namespace ImGui;
+	auto* const dl( GetWindowDrawList( ) );
+
+	PushFont( Globals::Window( ).smallFont( ) );
+	PushStyleColor( ImGuiCol_Text , ColHeaderText );
+	dl->AddRectFilled( bb.Min + ImVec2( 1 , 1 ) , bb.Max - ImVec2( 1 , 1 ) ,
+			ColHeader );
+	dl->AddRect( bb.Min , bb.Max , ColFrame );
+
+	const ImRect textBb{ bb.Min - ImVec2{ 10 , 0 } , bb.Max + ImVec2{ 10 , 0 } };
+	RenderTextClipped( textBb.Min , textBb.Max , "test!" , nullptr , nullptr , ImVec2{ 0 , .25 } , &bb );
+	RenderTextClipped( textBb.Min , textBb.Max , "...icle" , nullptr , nullptr , ImVec2{ 0 , .75 } , &bb );
+	PopStyleColor( );
+	PopFont( );
+}
+
 
 } // namespace
 /*= T_SyncView =================================================================*/

window.cc

@@ -1,6 +1,7 @@
 #include "externals.hh"
 #include "window.hh"
 #include "imgui_impl_sdl.h"
+#include <imgui_internal.h>
 
 
 T_Window::T_Window( )
@@ -27,6 +28,19 @@ T_Window::T_Window( )
 	}
 
 	ImGui_ImplSdl_Init( window );
+
+	using namespace ImGui;
+	ImGuiIO& io{ GetIO( ) };
+	{
+		ImFontConfig cfg;
+		cfg.SizePixels = 13.0f;
+		defaultFont_ = io.Fonts->AddFontDefault( &cfg );
+	}
+	{
+		ImFontConfig cfg;
+		cfg.SizePixels = 9.0f;
+		smallFont_ = io.Fonts->AddFontDefault( &cfg );
+	}
 }
 
 T_Window::~T_Window( )

window.hh

@@ -15,8 +15,15 @@ struct T_Window
 
 	void swap( ) const;
 
+	ImFont* defaultFont( ) const noexcept
+		{ return defaultFont_; }
+	ImFont* smallFont( ) const noexcept
+		{ return smallFont_; }
+
     private:
 	SDL_Window * window;
 	SDL_GLContext gl;
+	ImFont* defaultFont_;
+	ImFont* smallFont_;
 };