WIP

.github/workflows/main.yml

@@ -16,6 +16,16 @@ jobs:
       fail-fast: false
       matrix:
         CONDA_PY: ["36", "37", "38", "39"]
+        include:
+          - CONDA_PY: "36"
+            PYTHON_VERSION: "=3.6"
+          - CONDA_PY: "37"
+            PYTHON_VERSION: "=3.7"
+          - CONDA_PY: "38"
+            PYTHON_VERSION: "=3.8"
+          - CONDA_PY: "39"
+            PYTHON_VERSION: "=3.9"
+
 
     steps:
     - uses: actions/checkout@v2
@@ -33,13 +43,18 @@ jobs:
     - name: Install
       env:
         CONDA_PY: ${{ matrix.CONDA_PY }}
+        PYTHON_VERSION: ${{ matrix.PYTHON_VERSION }}
       run: |
         conda config --system --set always_yes yes --set changeps1 no
         conda install -c conda-forge conda-devenv
         conda info -a
         export TEST_QMXGRAPH=1
+        echo "=== conda devenv -n qmxgraph --print-full ==="
+        conda devenv -n qmxgraph --print-full
+        echo "=== === ==="
         conda devenv -n qmxgraph
         conda install -n qmxgraph coveralls pytest-cov
+        conda list -n qmxgraph
         conda init bash
     - name: Tests
       shell: bash -l {0}

environment.devenv.yml

@@ -1,6 +1,5 @@
 {% set TEST_QMXGRAPH = os.environ.get('TEST_QMXGRAPH', '0') != '0' %}
 {% set PYTHON_VERSION = os.environ.get('PYTHON_VERSION', '3.6') %}
-{% set PYTHON_VERSION = os.environ.get('TRAVIS_PYTHON_VERSION', PYTHON_VERSION) %}
 
 name: qmxgraph
 
@@ -15,6 +14,10 @@ environment:
 
 dependencies:
   - python ={{ PYTHON_VERSION }}
+  {% if "PYTHON_VERSION" in os.environ %}
+  - importlib_resources =1.3
+  - zipp =3.3
+  {% endif %}
 
   {% if TEST_QMXGRAPH %}
   - cherrypy

src/qmxgraph/configuration.py

@@ -61,6 +61,8 @@ class GraphOptions(object):
     :ivar bool show_outline: Show outline of graph in a floating window.
     :ivar bool snap_to_grid: Snap to background grid when moving vertices
         in graph.
+    :ivar bool zoom_to_cursor: Apply zoom focused on the position of the mouse cursor
+        instead of on the center.
     """
 
     allow_create_target = attr.ib(default=False, validator=_is_bool)
@@ -85,6 +87,7 @@ class GraphOptions(object):
     show_highlight = attr.ib(default=True, validator=_is_bool)
     show_outline = attr.ib(default=False, validator=_is_bool)
     snap_to_grid = attr.ib(default=True, validator=_is_bool)
+    zoom_to_cursor = attr.ib(default=False, validator=_is_bool)
 
     def as_dict(self):
         return attr.asdict(self)

src/qmxgraph/page/api.js

@@ -1241,6 +1241,9 @@ graphs.Api.prototype.registerViewUpdateHandler = function registerViewUpdateHand
     "use strict";
     var graph = this._graphEditor.graph;
     var listener = function (sender, evt) {
+        if (graph.getView().processingMouseWheel) {
+            return;
+        }
         handler(this.dump(), this.getScaleAndTranslation());
     }.bind(this);
     graph.getView().addListener(mxEvent.SCALE, listener);

src/qmxgraph/page/graphs.js

@@ -43,6 +43,8 @@ graphs.createGraph = function createGraph(container, options, styles) {
     var editor = new mxEditor();
     editor.setGraphContainer(container);
     var graph = editor.graph;
+    // Used to avoid sending events for the operations that are a part of zooming in/out.
+    graph.view.processingMouseWheel = false;
 
     // NOTE: grid size must usually equal the size of grid GIF
     // used as background of graph's div
@@ -509,6 +511,16 @@ graphs.createGraph = function createGraph(container, options, styles) {
 
     // * Adds mouse wheel handling for zoom
     mxEvent.addMouseWheelListener(function (evt, up) {
+        // Disable snapping, to make zooming in and out smoother.
+        let gridEnabled = graph.gridEnabled;
+        graph.gridEnabled = false;
+
+        let zoomToCursor = options["zoom_to_cursor"];
+        let view = graph.view;
+        view.processingMouseWheel = zoomToCursor;
+
+        let cursorBefore = graph.getPointForEvent(evt, false);
+
         // - `up = true` direction:
         //      Moves the viewport closer to the graph;
         //      When browsing a web page the vertical scrollbar will move up;
@@ -520,6 +532,17 @@ graphs.createGraph = function createGraph(container, options, styles) {
         } else {
             graph.zoomOut();
         }
+
+        if (zoomToCursor) {
+            view.processingMouseWheel = false;
+            let cursorAfter = graph.getPointForEvent(evt, false);
+            let deltaX = cursorAfter.x - cursorBefore.x;
+            let deltaY = cursorAfter.y - cursorBefore.y;
+            view.setTranslate(view.translate.x + deltaX, view.translate.y + deltaY);
+        }
+
+        graph.gridEnabled = gridEnabled;
+
         mxEvent.consume(evt);
     });