pixel access primitives for bitmap and vector graphics

HISTORY.md

@@ -20,6 +20,7 @@
     * new "play sound at sample rate" command
     * accept lists and lists of lists as inputs to all sound primitives
     * new "play frequency" commands in the Sounds category
+    * pixel access primitives for bitmap and vector (!) graphics
     * added "neg" selector to monadic function reporter in "Operators" category
     * added "log2" selector to monadic function reporter in "Operators" category
     * added "^" reporter (power of) in the Operators category
@@ -61,6 +62,9 @@
     * German
     * French
 
+### 2019-04-09
+* Blocks, Objects, Threads: new "getImageAttribute" reporter primitive
+
 ### 2019-04-08
 * Blocks, Objects, Threads: new "getSoundAttribute" reporter primitive
 * Blocks, Objects, Threads: new "play sound at sample rate" command primitive

snap.html

@@ -6,9 +6,9 @@
         <link rel="shortcut icon" href="src/favicon.ico">
         <script type="text/javascript" src="src/morphic.js?version=2019-02-07"></script>
         <script type="text/javascript" src="src/widgets.js?version=2019-04-05"></script>
-        <script type="text/javascript" src="src/blocks.js?version=2019-04-08"></script>
-        <script type="text/javascript" src="src/threads.js?version=2019-04-08"></script>
-        <script type="text/javascript" src="src/objects.js?version=2019-04-08"></script>
+        <script type="text/javascript" src="src/blocks.js?version=2019-04-09"></script>
+        <script type="text/javascript" src="src/threads.js?version=2019-04-09"></script>
+        <script type="text/javascript" src="src/objects.js?version=2019-04-09"></script>
         <script type="text/javascript" src="src/gui.js?version=2019-03-25"></script>
         <script type="text/javascript" src="src/paint.js?version=2019-02-22"></script>
         <script type="text/javascript" src="src/lists.js?version=2019-02-07"></script>

src/blocks.js

@@ -148,7 +148,7 @@ CustomCommandBlockMorph, SymbolMorph, ToggleButtonMorph, DialMorph*/
 
 // Global stuff ////////////////////////////////////////////////////////
 
-modules.blocks = '2019-April-08';
+modules.blocks = '2019-April-09';
 
 var SyntaxElementMorph;
 var BlockMorph;
@@ -1010,6 +1010,19 @@ SyntaxElementMorph.prototype.labelPart = function (spec) {
                 true // read-only
             );
             break;
+        case '%img': // image attributes
+            part = new InputSlotMorph(
+                null, // text
+                false, // numeric?
+                {
+                    'name' : ['name'],
+                    'width' : ['width'],
+                    'height' : ['height'],
+                    'pixels' : ['pixels']
+                },
+                true // read-only
+            );
+            break;
         case '%rate':
             part = new InputSlotMorph(
                 null,

src/objects.js

@@ -84,7 +84,7 @@ BlockEditorMorph, BlockDialogMorph, PrototypeHatBlockMorph, localize,
 TableMorph, TableFrameMorph, normalizeCanvas, BooleanSlotMorph, HandleMorph,
 AlignmentMorph, Process, XML_Element, VectorPaintEditorMorph*/
 
-modules.objects = '2019-April-08';
+modules.objects = '2019-April-09';
 
 var SpriteMorph;
 var StageMorph;
@@ -304,6 +304,12 @@ SpriteMorph.prototype.initBlocks = function () {
             category: 'looks',
             spec: 'costume #'
         },
+        reportGetImageAttribute: {
+            type: 'reporter',
+            category: 'looks',
+            spec: '%img of costume %cst',
+            defaults: [['width']]
+        },
         doSayFor: {
             only: SpriteMorph,
             type: 'command',
@@ -1994,6 +2000,8 @@ SpriteMorph.prototype.blockTemplates = function (category) {
         blocks.push(watcherToggle('getCostumeIdx'));
         blocks.push(block('getCostumeIdx', this.inheritsAttribute('costume #')));
         blocks.push('-');
+        blocks.push(block('reportGetImageAttribute'));
+        blocks.push('-');
         blocks.push(block('doSayFor'));
         blocks.push(block('bubble'));
         blocks.push(block('doThinkFor'));
@@ -7492,6 +7500,8 @@ StageMorph.prototype.blockTemplates = function (category) {
         blocks.push(watcherToggle('getCostumeIdx'));
         blocks.push(block('getCostumeIdx'));
         blocks.push('-');
+        blocks.push(block('reportGetImageAttribute'));
+        blocks.push('-');
         blocks.push(block('changeEffect'));
         blocks.push(block('setEffect'));
         blocks.push(block('clearEffects'));
@@ -8893,6 +8903,32 @@ Costume.prototype.thumbnail = function (extentPoint) {
     return trg;
 };
 
+// Costume pixel access
+
+Costume.prototype.rasterized = function () {
+    return this;
+};
+
+Costume.prototype.pixels = function () {
+    var i,
+        pixels = [],
+        src = this.contents.getContext('2d').getImageData(
+            0,
+            0,
+            this.contents.width,
+            this.contents.height
+        );
+    for (i = 0; i < src.data.length; i += 4) {
+        pixels.push(new List([
+            src.data[i],
+            src.data[i + 1],
+            src.data[i + 2],
+            src.data[i + 3]
+        ]));
+    }
+    return new List(pixels);
+};
+
 // Costume catching "tainted" canvases
 
 Costume.prototype.isTainted = function () {
@@ -9022,6 +9058,22 @@ SVG_Costume.prototype.edit = function (
     );
 };
 
+// SVG_Costume pixel access
+
+SVG_Costume.prototype.rasterized = function () {
+    var canvas = newCanvas(this.extent(), true),
+        ctx = canvas.getContext('2d'),
+        rasterized;
+
+    ctx.drawImage(this.contents, 0, 0);
+    rasterized = new Costume(
+        canvas,
+        this.name,
+        this.rotationCenter.copy()
+    );
+    return rasterized;
+};
+
 // CostumeEditorMorph ////////////////////////////////////////////////////////
 
 // CostumeEditorMorph inherits from Morph:

src/threads.js

@@ -62,7 +62,7 @@ StageMorph, SpriteMorph, StagePrompterMorph, Note, modules, isString, copy,
 isNil, WatcherMorph, List, ListWatcherMorph, alert, console, TableMorph, Color,
 TableFrameMorph, ColorSlotMorph, isSnapObject, Map*/
 
-modules.threads = '2019-April-08';
+modules.threads = '2019-April-09';
 
 var ThreadManager;
 var Process;
@@ -2291,7 +2291,7 @@ Process.prototype.doPlaySoundAtRate = function (name, rate) {
     }
     source.pause = source.stop;
     source.ended = false;
-    source.onended = function () {this.ended = true; }
+    source.onended = function () {this.ended = true; };
     source.start();
     rcvr.parentThatIsA(StageMorph).activeSounds.push(source);
     return source;
@@ -2420,7 +2420,7 @@ Process.prototype.encodeSound = function (samples, rate) {
     }
     source = ctx.createBufferSource();
     source.buffer = arrayBuffer;
-    source.audioBuffer = source.buffer; // +++
+    source.audioBuffer = source.buffer;
     return source;
 };
 
@@ -4335,6 +4335,33 @@ Process.prototype.doSetInstrument = function (num) {
     }
 };
 
+// Process image processing primitives
+
+Process.prototype.reportGetImageAttribute = function (choice, name) {
+    var cst = name instanceof Costume ? name
+            : (typeof name === 'number' ?
+                    this.blockReceiver().costumes.at(name)
+                : detect(
+                    this.blockReceiver().costumes.asArray(),
+                    function (c) {return c.name === name.toString(); }
+                )
+            ),
+        option = this.inputOption(choice);
+
+    switch (option) {
+    case 'name':
+        return cst.name;
+    case 'width':
+        return cst.width();
+    case 'height':
+        return cst.height();
+    case 'pixels':
+        return cst.rasterized().pixels();
+    default:
+        return 0;
+    }
+};
+
 // Process constant input options
 
 Process.prototype.inputOption = function (dta) {