Add imageprovider and improve threading support (#235)

Author: barche

Project.toml

@@ -1,6 +1,6 @@
 name = "QML"
 uuid = "2db162a6-7e43-52c3-8d84-290c1c42d82a"
-version = "0.12.1"
+version = "0.13.0"
 authors = ["Bart Janssens <bart@bartjanssens.org>"]
 
 [deps]
@@ -28,9 +28,9 @@ ColorTypes = "0.11, 0.12"
 CxxWrap = "0.17.5"
 MacroTools = "0.5"
 Observables = "0.5"
-Qt6Svg_jll = "6.8"
-Qt6Wayland_jll = "6.8"
-jlqml_jll = "0.9.0"
+Qt6Svg_jll = "6.10"
+Qt6Wayland_jll = "6.10"
+jlqml_jll = "0.10.0"
 julia = "1.10"
 
 [extras]

src/QML.jl

@@ -88,6 +88,9 @@ Load a QML file, creating a [`QML.QQmlApplicationEngine`](@ref), and setting the
 """
 function loadqml(qmlfilename; kwargs...)
   qml_engine = init_qmlapplicationengine()
+  return loadqml(qml_engine, qmlfilename; kwargs...)
+end
+function loadqml(qml_engine,qmlfilename; kwargs...)
   ctx = root_context(CxxRef(qml_engine))
   for (key,value) in kwargs
     set_context_property(ctx, String(key), value)
@@ -208,6 +211,7 @@ function Base.iterate(s::QString, i::Integer=1)
 end
 Base.convert(::Type{<:QString}, s::String) = QString(s)
 QString(u::QUrl) = toString(u)
+@cxxdereference Base.show(io::IO, u::QUrl) = print(io, toString(u))
 
 # QByteArray
 Base.convert(::Type{QByteArray}, s::AbstractString) = QByteArray(s)
@@ -310,6 +314,14 @@ Base.iterate(h::QMap, state::QMapIterator) = _qmap_iteration_tuple(h, iteratorne
 Base.values(h::QMap) = QML.values(h)
 Base.keys(h::QMap) = QML.keys(h)
 
+#QTimer helper
+function QTimer(f, interval)
+  timer = QTimer()
+  setInterval(timer, interval)
+  callOnTimeout(timer, f)
+  start(timer)
+end
+
 # Helper to call a julia function
 function julia_call(f, argptr::Ptr{Cvoid})
   arglist = CxxRef{QVariantList}(argptr)[]
@@ -409,17 +421,26 @@ JuliaPropertyMap(dict::Dict{<:AbstractString,<:Any}) = JuliaPropertyMap(dict...)
 
 @cxxdereference value(::Type{JuliaPropertyMap}, qvar::QVariant) = getpropertymap(qvar)
 
-const _queued_properties = []
-
 # Functor to update a QML property when an Observable is changed in Julia
 struct QmlPropertyUpdater
   propertymap::QQmlPropertyMap
   key::String
   active::Bool
 end
+
+const _queued_properties = Dict{QmlPropertyUpdater,Any}()
+const _queue_lock = ReentrantLock()
+_called_update = false;
+
 function (updater::QmlPropertyUpdater)(x)
   if Base.current_task() != Base.roottask
-    push!(_queued_properties, (updater, x))
+    @lock _queue_lock begin 
+      _queued_properties[updater] = x
+      if !_called_update
+        queue_process_eventloop_updates()
+        global _called_update = true
+      end
+    end
     return
   end
   updater.propertymap[updater.key] = x
@@ -445,6 +466,10 @@ macro deferredcall(expr)
       $(esc(expr))
     else
       put!(_deferred_calls, () -> $(esc(expr)))
+      @lock _queue_lock if !_called_update
+        queue_process_eventloop_updates()
+        global _called_update = true
+      end
       nothing
     end
   end
@@ -669,6 +694,7 @@ function Base.displayable(d::JuliaDisplay, mime::AbstractString)
 end
 
 include("itemmodel.jl")
+include("imageprovider.jl")
 
 function exec()
   # We redirect to the Core stdout/err in case threading is used
@@ -687,7 +713,21 @@ function exec()
   return
 end
 
+# Runs all observable and model updates that need to be done on the main event loop
+# Updates are cached here when they were made from a task different from the Julia root task
+function process_eventloop_updates()
+  @lock _queue_lock begin
+    for (updater, x) in _queued_properties
+      updater.propertymap[updater.key] = x
+    end
+    empty!(_queued_properties)
+    run_deferred_calls()
+    global _called_update = false
+  end
+end
+
 function exec_async()
+  global _called_update = true # No need to queue event loop updates to the main thread
   lastdisplay = popdisplay()
   if VERSION >= v"1.12-"
     newrepl = @async Base.run_main_repl(true,true,:yes,true)
@@ -701,11 +741,8 @@ function exec_async()
   pushdisplay(lastdisplay)
 
   while !istaskdone(newrepl)
-      for (updater, x) in _queued_properties
-        updater.propertymap[updater.key] = x
-      end
-      empty!(_queued_properties)
-      run_deferred_calls()
+      process_eventloop_updates()
+      global _called_update = true
       process_events()
       sleep(0.015)
   end

src/imageprovider.jl

@@ -0,0 +1,30 @@
+export ImageProvider, QImage, QPixmap, QColor, QSize, setcallback, addImageProvider
+
+# Wrapper for the C++ type for easier construction and
+# keeping a reference to the callback to prevent GC
+mutable struct ImageProvider
+  provider::JuliaImageProvider # The C++ object
+  callback
+
+  function ImageProvider(imagetype, callback)
+    provider_cpp = JuliaImageProvider(imagetype)
+    provider = new(provider_cpp)
+    setcallback(provider, callback)
+    return provider
+  end
+end
+
+function setcallback(provider, callback)
+  callback_imageresult(id, w, h) = ImageResult(callback(id, w, h)...)
+  callback_c = @CxxWrap.safe_cfunction($callback_imageresult, Any, (ConstCxxRef{QString},Cint,Cint))
+  set_callback(provider.provider, callback_c)
+  provider.callback = callback_c
+  return
+end
+
+Base.deepcopy(image::QImage) = QML.copy(image)
+
+@cxxdereference addImageProvider(engine, id, provider::ImageProvider) = QML.addImageProvider(engine, id, CxxPtr(provider.provider))
+
+ImageResult(image::QImage, width, height) = QML.ImageResult{QImage}(image, Int32(width), Int32(height))
+ImageResult(image::QPixmap, width, height) = QML.ImageResult{QPixmap}(image, Int32(width), Int32(height))

test/imageprovider.jl

@@ -0,0 +1,84 @@
+using QML
+using Test
+
+qmlfile = joinpath(dirname(@__FILE__), "qml", "imageprovider.qml")
+
+"""
+    make_qimage_rgb888(rgb::NTuple{3, Integer}, width::Integer, height::Integer)
+        -> (buf::Vector{UInt8}, bytes_per_line::Int)
+
+Create a flat `Vector{UInt8}` containing pixel data for a solid-color image in
+**QImage::Format_RGB888** (3 bytes/pixel in R, G, B order), laid out row-major.
+
+Returns the buffer and `bytes_per_line` (stride) which you pass to `QImage`.
+
+Notes:
+- The buffer is tightly packed: `bytes_per_line == 3 * width`.
+- Keep a Julia reference to `buf` alive for as long as Qt may read it,
+  unless your C++ side deep-copies the image data.
+"""
+function make_qimage_rgb888(rgb::NTuple{3, Integer}, width::Integer, height::Integer)
+  w = Int(width);  h = Int(height)
+  (w > 0 && h > 0) || throw(ArgumentError("width and height must be positive"))
+
+  r = UInt8(clamp(rgb[1], 0, 255))
+  g = UInt8(clamp(rgb[2], 0, 255))
+  b = UInt8(clamp(rgb[3], 0, 255))
+
+  bytes_per_line = 3 * w
+  buf = Vector{UInt8}(undef, h * bytes_per_line)
+
+  # Build one scanline and copy it h times — fast and branch-free
+  @inbounds begin
+    row = Vector{UInt8}(undef, bytes_per_line)
+    for x in 0:w-1
+      i = 3x + 1
+      row[i]   = r
+      row[i+1] = g
+      row[i+2] = b
+    end
+    for y in 0:h-1
+      dest = y * bytes_per_line + 1
+      copyto!(buf, dest, row, 1, bytes_per_line)
+    end
+  end
+
+  return buf, bytes_per_line
+end
+
+function image_callback(id, requestedwidth, requestedheight)
+  width = requestedwidth <= 0 ? 100 : requestedwidth
+  height = requestedheight <= 0 ? 100 : requestedheight
+
+  color = (0,0,0)
+  if id[] == "yellow"
+      color = (255,255,0)
+  elseif id[] == "red"
+      color = (255,0,0)
+  end
+
+  buf, stride = make_qimage_rgb888(color, width, height)
+  image = QImage(pointer(buf), width, height, stride, QML.Format_RGB888)
+  return deepcopy(image), width, height
+end
+
+function pixmap_callback(id, requestedwidth, requestedheight)
+  width = requestedwidth <= 0 ? 100 : requestedwidth
+  height = requestedheight <= 0 ? 100 : requestedheight
+
+  pixmap = QPixmap(width, height)
+  QML.fill(pixmap, QColor(id))
+
+  return pixmap, width, height
+end
+
+imageprovider = ImageProvider(QML.Image, image_callback)
+pixmapprovider = ImageProvider(QML.Pixmap, pixmap_callback)
+engine = init_qmlapplicationengine()
+
+addImageProvider(engine, "images", imageprovider)
+addImageProvider(engine, "pixmaps", pixmapprovider)
+
+loadqml(engine, qmlfile)
+exec()
+

test/qml/imageprovider.qml

@@ -0,0 +1,58 @@
+import QtQuick
+import QtQuick.Controls
+import QtQuick.Layouts
+
+ApplicationWindow {
+  visible: true
+  width: 320
+  height: 240
+
+  RowLayout {
+    anchors.fill: parent
+    ColumnLayout {
+      Layout.fillWidth: true
+      Layout.fillHeight: true
+      Image {
+        source: "image://images/yellow"
+        Layout.fillWidth: true
+        Layout.fillHeight: true
+        sourceSize.width: width
+        sourceSize.height: height
+      }
+      Image { 
+        source: "image://images/red"
+        Layout.fillWidth: true
+        Layout.fillHeight: true
+        sourceSize.width: width
+        sourceSize.height: height
+      }
+    }
+    Image {
+      source: "image://pixmaps/black"
+      Layout.fillWidth: true
+      Layout.fillHeight: true
+      sourceSize.width: width
+      sourceSize.height: height
+    }
+    Image { 
+      source: "image://images/yellow"
+      Layout.fillWidth: true
+      Layout.fillHeight: true
+      sourceSize.width: width
+      sourceSize.height: height
+    }
+    Image { 
+      source: "image://images/red"
+      Layout.fillWidth: true
+      Layout.fillHeight: true
+      sourceSize.width: width
+      sourceSize.height: height
+    }
+  }
+
+  Timer {
+    interval: 1000; running: true; repeat: false
+    onTriggered: Qt.exit(0)
+  }
+
+}

test/qstring.jl

@@ -16,3 +16,11 @@ let strings = ["TestStr", "😁😃😆abc😎😈☹"]
 
   @test strings == qsl
 end
+
+let filename = "test.txt"
+  uri = QUrlFromLocalFile(filename)
+  uri_repr = repr(uri)
+  @test startswith(uri_repr, "file")
+  @test endswith(uri_repr, filename)
+  @test QML.toLocalFile(uri) == filename
+end