melrōse musical expression player

package server import ( "fmt" "net/http" "time" "github.com/emicklei/melrose/core" "github.com/emicklei/melrose/midi" "github.com/emicklei/melrose/notify" "github.com/emicklei/melrose/ui/img" "github.com/fogleman/gg" ) // pianorollImageHandler returns PNG content given a variable func (l *LanguageServer) pianorollImageHandler(w http.ResponseWriter, r *http.Request) { if r.Method != http.MethodGet { w.WriteHeader(http.StatusMethodNotAllowed) notify.Console.Warnf("HTTP method not allowed:%s", r.Method) return } varname := r.URL.Query().Get("var") if varname == "" { w.WriteHeader(http.StatusBadRequest) fmt.Fprintf(w, "var parameter is empty") return } obj, ok := l.context.Variables().Get(varname) if !ok { w.WriteHeader(http.StatusBadRequest) fmt.Fprintf(w, "no object found for var:%s", varname) return } seq, ok := obj.(core.Sequenceable) if !ok { w.WriteHeader(http.StatusBadRequest) fmt.Fprintf(w, "no object is not sequenceable:%s", varname) return } tim := core.NewTimeline() d := midi.NewOutputDevice(0, nil, 0, tim) d.Play(core.NoCondition, seq, l.context.Control().BPM(), time.Now()) gc := gg.NewContext(1000, 200) evts := tim.NoteEvents() nv := img.NotesView{Events: evts, BPM: l.context.Control().BPM()} nv.DrawOn(gc) w.Header().Set("content-type", "image/png") gc.EncodePNG(w) }