drawbuf pixel storage optimizations - don't use GC: #499

src/dlangui/core/types.d

@@ -643,3 +643,76 @@ dstring normalizeEndOfLineCharacters(dstring s) {
     }
     return cast(dstring)res;
 }
+
+/// C malloc allocated array wrapper
+struct MallocBuf(T) {
+    import core.stdc.stdlib : realloc, free;
+    private T * _allocated;
+    private uint _allocatedSize;
+    private uint _length;
+    /// get pointer
+    @property T * ptr() { return _allocated; }
+    /// get length
+    @property uint length() { return _length; }
+    /// set new length
+    @property void length(uint len) {
+        if (len > _allocatedSize) {
+            reserve(_allocatedSize ? len * 2 : len);
+        }
+        _length = len;
+    }
+    /// const array[index];
+    T opIndex(uint index) const {
+        assert(index < _length);
+        return _allocated[index];
+    }
+    /// ref array[index];
+    ref T opIndex(uint index) {
+        assert(index < _length);
+        return _allocated[index];
+    }
+    /// array[index] = value;
+    void opIndexAssign(uint index, T value) {
+        assert(index < _length);
+        _allocated[index] = value;
+    }
+    /// array[index] = value;
+    void opIndexAssign(uint index, T[] values) {
+        assert(index + values.length < _length);
+        _allocated[index .. index + values.length] = values[];
+    }
+    /// array[a..b]
+    T[] opSlice(uint a, uint b) {
+        assert(a <= b && b <= _length);
+        return _allocated[a .. b];
+    }
+    /// array[]
+    T[] opSlice() {
+        return _allocated ? _allocated[0 .. _length] : null;
+    }
+    /// array[$]
+    uint opDollar() { return _length; }
+    ~this() {
+        clear();
+    }
+    /// free allocated memory, set length to 0
+    void clear() {
+        if (_allocated)
+            free(_allocated);
+        _allocatedSize = 0;
+        _length = 0;
+    }
+    /// make sure buffer capacity is at least (size) items
+    void reserve(uint size) {
+        if (_allocatedSize < size) {
+            _allocated = cast(T*)realloc(_allocated, T.sizeof * size);
+            _allocatedSize = size;
+        }
+    }
+    /// fill buffer with specified value
+    void fill(T value) {
+        if (_length) {
+            _allocated[0 .. _length] = value;
+        }
+    }
+}

src/dlangui/graphics/drawbuf.d

@@ -1233,14 +1233,15 @@ class ColorDrawBufBase : DrawBuf {
 }
 
 class GrayDrawBuf : DrawBuf {
-    int _dx;
-    int _dy;
+    protected int _dx;
+    protected int _dy;
     /// returns buffer bits per pixel
     override @property int bpp() { return 8; }
     @property override int width() { return _dx; }
     @property override int height() { return _dy; }
 
-    ubyte[] _buf;
+    protected MallocBuf!ubyte _buf;
+
     this(int width, int height) {
         resize(width, height);
     }
@@ -1473,7 +1474,7 @@ class GrayDrawBuf : DrawBuf {
 }
 
 class ColorDrawBuf : ColorDrawBufBase {
-    uint[] _buf;
+    protected MallocBuf!uint _buf;
 
     /// create ARGB8888 draw buf of specified width and height
     this(int width, int height) {
@@ -1482,9 +1483,8 @@ class ColorDrawBuf : ColorDrawBufBase {
     /// create copy of ColorDrawBuf
     this(ColorDrawBuf v) {
         this(v.width, v.height);
-        //_buf.length = v._buf.length;
-        foreach(i; 0 .. _buf.length)
-            _buf[i] = v._buf[i];
+        if (auto len = _buf.length)
+            _buf.ptr[0 .. len] = v._buf.ptr[0 .. len];
     }
     /// create resized copy of ColorDrawBuf
     this(ColorDrawBuf v, int dx, int dy) {
@@ -1494,7 +1494,7 @@ class ColorDrawBuf : ColorDrawBufBase {
     }
 
     void invertAndPreMultiplyAlpha() {
-        foreach(ref pixel; _buf) {
+        foreach(ref pixel; _buf[]) {
             uint a = (pixel >> 24) & 0xFF;
             uint r = (pixel >> 16) & 0xFF;
             uint g = (pixel >> 8) & 0xFF;
@@ -1510,12 +1510,12 @@ class ColorDrawBuf : ColorDrawBufBase {
     }
 
     void invertAlpha() {
-        foreach(ref pixel; _buf)
+        foreach(ref pixel; _buf[])
             pixel ^= 0xFF000000;
     }
 
     void invertByteOrder() {
-        foreach(ref pixel; _buf) {
+        foreach(ref pixel; _buf[]) {
             pixel = (pixel & 0xFF00FF00) |
                 ((pixel & 0xFF0000) >> 16) |
                 ((pixel & 0xFF) << 16);
@@ -1524,7 +1524,7 @@ class ColorDrawBuf : ColorDrawBufBase {
 
     // for passing of image to OpenGL texture
     void invertAlphaAndByteOrder() {
-        foreach(ref pixel; _buf) {
+        foreach(ref pixel; _buf[]) {
             pixel = ((pixel & 0xFF00FF00) |
                 ((pixel & 0xFF0000) >> 16) |
                 ((pixel & 0xFF) << 16));
@@ -1643,9 +1643,9 @@ class ColorDrawBuf : ColorDrawBufBase {
         uint[] tmpbuf;
         tmpbuf.length = _buf.length;
         // do horizontal blur
-        blurOneDimension(_buf, tmpbuf, blurSize, true);
+        blurOneDimension(_buf[], tmpbuf, blurSize, true);
         // then do vertical blur
-        blurOneDimension(tmpbuf, _buf, blurSize, false);
+        blurOneDimension(tmpbuf, _buf[], blurSize, false);
     }
 }