Fixes & improvements to Image, including scaling & arbitrary rotation.

This commit adds bilinear interpolation scaling and arbirary rotation
methods to `Image`.
In the process, several issues with `Image` were found & fixed:

* There was no destructor to free the `canvas` memory. This would
  cause a memory leak unless the client remembered to call `close()`
  A virtual destructor has been added to free this memory.

* There was no explicit copy & move constructor for `Image`
  This means whenever Image was copied or passed by value
  a 'shallow copy' was performed resulting in both instances
  referencing the same shared canvas memory.
  This works, and several examples were depending on it, but
  after the addition of the destructor it caused seg faults since
  the memory was free()'d several times.
  An explicit copy constuctor for `Image` has been added to
  perform a 'deep copy' of the `canvas` memory.
  A C++11 'move' constructor has been added to avoid excessive
  deep copies being made when passing `Image` as a temporary.

* The same logic for copy/move constructors also applies to
  assignment operators (operator=()) so these are added.

* `Image` (and `Color`) are extensively passed by value within
  the library. This now potentially inefficient due to the deep copy.
  (if the move c'tor is not used)
  Since pass-by-reference semantics are required in these cases they
  are now passed by reference.

* Pass-by-(const)-reference changes also required many methods on `Image`
  and `Color` that did not modify their members to be declared `const`
  as well as all `Color` preset constants.

* New c'tors and getters added to `Color` to support RGBA
  access as required by the new scaling method on `Image`
  Also tidied up c'tors to use common helper methods.

* Used new/delete instead of malloc/free for heap memory use  in `Image`
  Just coz it's more conventional in C++

Author: neildavis

example/demo1.cpp

@@ -41,7 +41,7 @@ unsigned long long currentTimeMillis() {
 }
 
 
-void drawSine(Image image, float offset, float speed, int maxX, int maxY, float waveHeight, Color color, int width) {
+void drawSine(Image &image, float offset, float speed, int maxX, int maxY, float waveHeight, Color color, int width) {
     bool first = true;;
     int lx = -1, ly = -1;
     double vx = 0;
@@ -62,7 +62,7 @@ void drawSine(Image image, float offset, float speed, int maxX, int maxY, float
 }
 
 
-bool demoSineWave(int frameCount, long long start, Image image) {
+bool demoSineWave(int frameCount, long long start, Image &image) {
     long long now = currentTimeMillis();
     float refVoltage = 5;
 
@@ -148,6 +148,29 @@ void rotationDemo() {
 
 }
 
+void imageRotationDemo(Image &img) {
+    Image srcImg = img.scale(0.75f, 0.75f, BILINEAR);
+    for (int deg = 0; deg < 360; deg += 5) {
+        printf("Rotate: %d degrees CW\n", deg);  fflush(stdout);
+        d1.showImage(srcImg.rotate(deg, DEGREES), DEGREE_270);
+    }
+    for (int deg = 0; deg > -360; deg -= 5) {
+        printf("Rotate: %d degrees CCW\n", deg);  fflush(stdout);
+        d1.showImage(srcImg.rotate(deg, DEGREES), DEGREE_270);
+    }
+}
+
+void imageScalingDemo(Image &img) {
+    for (int i = 100; i > 0; i -= 10) {
+        float scale = i / 100.0f;
+        d1.showImage(img.scale(scale, scale, BILINEAR), DEGREE_270);
+    }
+    for (int i = 20; i <= 200; i += 10) {
+        float scale = i / 100.0f;
+        d1.showImage(img.scale(scale, scale, BILINEAR), DEGREE_270);
+    }
+}
+
 void display1Demo() {
     printf("demo1\n"); fflush(stdout);
 
@@ -170,8 +193,8 @@ void display1Demo() {
         delay(solidsDelay);
         d1.clearScreen(BLACK);
 
-        d1.showImage(bmp, DEGREE_270);
-        delay(2000);
+        imageRotationDemo(bmp);
+        imageScalingDemo(bmp);
 
         rotationDemo();
         delay(4000);
@@ -189,6 +212,7 @@ void configureDisplay1() {
     d1Config.width = 240;
     d1Config.height = 320;
     d1Config.spiSpeed = spiSpeed;
+    d1Config.spiMode = 0;
 
     d1Config.CS = 21;
     d1Config.DC = 22;
@@ -215,14 +239,6 @@ int main(int argc, char **argv)
     digitalWrite(10, HIGH);
     digitalWrite(11, HIGH);
 
-    int         demos = 3;
-    pthread_t   threads[demos];
-    char        message[demos][256];
-
-    for (int i = 0; i < demos; ++i) {
-        sprintf(message[i], "demo thread %d", i);
-    }
-
     configureDisplay1();
 
     printf("press control-c to quit\n");

example/demo2.cpp

@@ -42,7 +42,7 @@ unsigned long long currentTimeMillis() {
 }
 
 
-void drawSine(Image image, float offset, float speed, int maxX, int maxY, float waveHeight, Color color, int width) {
+void drawSine(Image &image, float offset, float speed, int maxX, int maxY, float waveHeight, Color color, int width) {
     bool first = true;;
     int lx = -1, ly = -1;
     double vx = 0;
@@ -63,7 +63,7 @@ void drawSine(Image image, float offset, float speed, int maxX, int maxY, float
 }
 
 
-bool demoSineWave(int frameCount, long long start, Image image) {
+bool demoSineWave(int frameCount, long long start, Image &image) {
     long long now = currentTimeMillis();
     float refVoltage = 5;
 

example/neopixel2.cpp

@@ -73,7 +73,7 @@ unsigned long long currentTimeMillis() {
 }
 
 
-void drawSine(Image image, float offset, float speed, int maxX, int maxY, float waveHeight, Color color, int width) {
+void drawSine(Image &image, float offset, float speed, int maxX, int maxY, float waveHeight, Color color, int width) {
     bool first = true;
     int lx = -1, ly = -1;
     double vx = 0;
@@ -94,7 +94,7 @@ void drawSine(Image image, float offset, float speed, int maxX, int maxY, float
 }
 
 
-bool demoSineWave(int frameCount, long long start, Image image) {
+bool demoSineWave(int frameCount, long long start, Image &image) {
     long long now = currentTimeMillis();
     float refVoltage = 5;
 
@@ -394,7 +394,7 @@ void* setBrightness(void *) {
 
     int startTime=currentTimeMillis();
     for (int i=0;i<4;++i) {
-      float v=readVoltage(handle, i, 0);
+      float v=readVoltage(handle);
       if (v>6) {
         v=0;
       }

example/wsePaperV2.cpp

@@ -39,7 +39,7 @@ unsigned long long currentTimeMillis() {
 }
 
 
-void drawSine(Image image, float offset, float speed, int maxX, int maxY, float waveHeight, Color color, int width) {
+void drawSine(Image &image, float offset, float speed, int maxX, int maxY, float waveHeight, Color color, int width) {
     bool first = true;;
     int lx = -1, ly = -1;
     double vx = 0;
@@ -60,7 +60,7 @@ void drawSine(Image image, float offset, float speed, int maxX, int maxY, float
 }
 
 
-bool demoSineWave(int frameCount, long long start, Image image) {
+bool demoSineWave(int frameCount, long long start, Image &image) {
     long long now = currentTimeMillis();
     float refVoltage = 5;
 

src/controller/Color.cpp

@@ -9,22 +9,22 @@ Color::Color() {
     color.opacity = 255;
 }
 
-
 Color::Color(ColorType color) {
-    this->color.red = color.red;
-    this->color.green = color.green;
-    this->color.blue = color.blue;
-    this->color.opacity = color.opacity;
+    memcpy(&this->color, &color, sizeof(ColorType));
 }
 
-
 Color::Color(_byte red, _byte green, _byte blue) {
-    color.red = red;
-    color.green = green;
-    color.blue = blue;
-    color.opacity = 255;
+    setColor(red, green, blue, 255);
+}
+
+Color::Color(_byte red, _byte green, _byte blue, _byte opacity) {
+    setColor(red, green, blue, opacity);
 }
 
+Color::Color(uint32_t colorRGB24) {
+    setRGB24(colorRGB24);
+}
+ 
 Color::Color(const char* hexbytes) {
     char buf[3];
     int intensity;
@@ -68,63 +68,37 @@ Color::Color(const char* hexbytes) {
     }
 }
 
-bool Color::equals(Color otherColor) {
-    if (this->color.blue != otherColor.color.blue) {
-        return false;
-    }
-    if (this->color.red!= otherColor.color.red) {
-        return false;
-    }
-    if (this->color.green != otherColor.color.green) {
-        return false;
-    }
-    return true;
+bool Color::equals(const Color &otherColor) const {
+    return equals(otherColor.color);
 }
 
-bool Color::equals(ColorType otherColor) {
-    if (this->color.blue != otherColor.blue) {
+bool Color::equals(const ColorType &otherColor) const {
+    if (color.blue != otherColor.blue) {
         return false;
     }
-    if (this->color.red != otherColor.red) {
+    if (color.red != otherColor.red) {
         return false;
     }
-    if (this->color.green != otherColor.green) {
+    if (color.green != otherColor.green) {
         return false;
     }
     return true;
 }
 
-bool Color::equals(ColorType *otherColor) {
-    if (this->color.blue != otherColor->blue) {
-        return false;
-    }
-    if (this->color.red != otherColor->red) {
-        return false;
-    }
-    if (this->color.green != otherColor->green) {
-        return false;
-    }
-    return true;
-}
-
-
-Color::Color(_byte red, _byte green, _byte blue, _byte opacity) {
-    color.red       = red;
-    color.green     = green;
-    color.blue      = blue;
-    color.opacity   = opacity;
-}
-
-ColorType Color::toType() {
-    return color;
+inline void Color::setColor(_byte red, _byte green, _byte blue, _byte opacity) {
+    color.red = red;
+    color.green = green;
+    color.blue = blue;
+    color.opacity = opacity;
 }
 
-
-int32_t Color::rgb24() {
-    return (color.green<<16)+(color.red<<8)+(color.blue);
+inline void Color::setRGB24(uint32_t colorRGB24) {
+    color.red = (_byte)(colorRGB24 & 0xFF);
+    color.green = (_byte)((colorRGB24 & 0xFF00) >> 8);
+    color.blue = (_byte)((colorRGB24 & 0xFF0000) >> 16);
+    color.opacity = (_byte)((colorRGB24 & 0xFF000000) >> 24);
 }
 
-
 Color::Color(int clr) {
     color.opacity = 255;
 
@@ -150,7 +124,7 @@ Color::Color(int clr) {
 }
 
 
-void Color::print() {
+void Color::print() const {
 
     printf("color::print: 0x%02x%02x%02x\n", this->color.red, this->color.blue,this->color.green);
     printf("color::print: 0x%02x%02x%02x\n", color.red, color.blue, color.green);
@@ -164,26 +138,26 @@ void Color::print() {
 
 
 // Original 8
-Color BLACK             = Color(0,     0,   0);
-Color RED               = Color(255,   0,   0);
-Color GREEN             = Color(0,   255,   0);
-Color BLUE              = Color(0,     0, 255);
-Color YELLOW            = Color(255, 255,   0);
-Color MAGENTA           = Color(255,   0, 255);
-Color CYAN              = Color(0,   255, 255);
-Color WHITE             = Color(255, 255, 255);
+const Color BLACK             = Color(0,     0,   0);
+const Color RED               = Color(255,   0,   0);
+const Color GREEN             = Color(0,   255,   0);
+const Color BLUE              = Color(0,     0, 255);
+const Color YELLOW            = Color(255, 255,   0);
+const Color MAGENTA           = Color(255,   0, 255);
+const Color CYAN              = Color(0,   255, 255);
+const Color WHITE             = Color(255, 255, 255);
 
 // extended colors
-Color GRAY              = Color("#808080");
-Color BROWN             = Color(165,  42,  42);
-Color ORANGE            = Color(255, 128,   0);
+const Color GRAY              = Color("#808080");
+const Color BROWN             = Color(165,  42,  42);
+const Color ORANGE            = Color(255, 128,   0);
 
-Color DARK_RED          = Color(128,   0,   0);
-Color DARK_GREEN        = Color(0,   128,   0);
-Color DARK_BLUE         = Color(0,     0, 128);
+const Color DARK_RED          = Color(128,   0,   0);
+const Color DARK_GREEN        = Color(0,   128,   0);
+const Color DARK_BLUE         = Color(0,     0, 128);
 
 
-Color LIGHT_BLUE        = Color(204, 228, 255);
-Color LIGHT_GRAY        = Color("#E0E0E0");
+const Color LIGHT_BLUE        = Color(204, 228, 255);
+const Color LIGHT_GRAY        = Color("#E0E0E0");
 
-Color DARK_GRAY_BLUE    = Color("003366");
+const Color DARK_GRAY_BLUE    = Color("003366");

src/controller/Color.h

@@ -12,49 +12,54 @@ struct ColorStruct {
 
 typedef ColorStruct ColorType;
 
+inline uint32_t   getRGB24(const ColorType *color) {
+   return (color->opacity << 24 ) | (color->blue << 16) | (color->green << 8) | color->red;
+}
 
 class Color {
 public:
     ColorType color;
 
     Color();
     Color(ColorType color);
-    Color(_byte red, _byte blue, _byte green);
+    Color(_byte red, _byte green, _byte blue);
+    Color(_byte red, _byte green, _byte blue, _byte opacity);
+    Color(uint32_t colorRGB24);
     Color(const char *hexbytes);
-    Color(_byte red, _byte blue, _byte green, _byte opacity);
-
+ 
     Color(int pos);
 
-    ColorType toType();
-    int32_t   rgb24();
-    void      print();
-    bool      equals(Color otherColor);
-    bool      equals(ColorType otherColor);
-    bool      equals(ColorType *otherColor);
+    inline ColorType toType() const { return color; }
+    inline uint32_t rgb24() const { return getRGB24(&color); }
+    inline void setColor(_byte red, _byte green, _byte blue, _byte opacity);
+    inline void setRGB24(uint32_t colorRGB24);
+    void      print() const;
+    bool      equals(const Color &otherColor) const;
+    bool      equals(const ColorType &otherColor) const;
 
 };
 
 
 // original 8
-extern Color BLACK;
-extern Color RED;
-extern Color GREEN;
-extern Color BLUE;
-extern Color YELLOW;
-extern Color MAGENTA;
-extern Color CYAN;
-extern Color WHITE;
-
-extern Color GRAY;
-extern Color BROWN;
-extern Color ORANGE;
-
-extern Color LIGHT_BLUE;
-extern Color LIGHT_GRAY;
-
-extern Color DARK_BLUE;
-extern Color DARK_RED;
-extern Color DARK_GREEN;
-
-extern Color DARK_GRAY_BLUE;
+extern const Color BLACK;
+extern const Color RED;
+extern const Color GREEN;
+extern const Color BLUE;
+extern const Color YELLOW;
+extern const Color MAGENTA;
+extern const Color CYAN;
+extern const Color WHITE;
+
+extern const Color GRAY;
+extern const Color BROWN;
+extern const Color ORANGE;
+
+extern const Color LIGHT_BLUE;
+extern const Color LIGHT_GRAY;
+
+extern const Color DARK_BLUE;
+extern const Color DARK_RED;
+extern const Color DARK_GREEN;
+
+extern const Color DARK_GRAY_BLUE;