Only allocate canvas portion pixels when needed

This will allow for larger renders in constant memory footprint

src/interface/desktop/formrender.cpp

@@ -36,8 +36,8 @@ BaseForm(parent, true)
 
     addInput(new InputCamera(this, tr("Camera"), _camera));
     addInputInt(tr("Quality"), &_params.quality, 1, 10, 1, 1);
-    addInputInt(tr("Image width"), &_params.width, 100, 2000, 10, 100);
-    addInputInt(tr("Image height"), &_params.height, 100, 1200, 10, 100);
+    addInputInt(tr("Image width"), &_params.width, 100, 4000, 10, 100);
+    addInputInt(tr("Image height"), &_params.height, 100, 3000, 10, 100);
     addInputInt(tr("Anti aliasing"), &_params.antialias, 1, 4, 1, 1);
 
     button = addButton(tr("Start new render"));

src/render/software/Canvas.cpp

@@ -67,8 +67,13 @@ void Canvas::setSize(int width, int height)
     this->width = width;
     this->height = height;
 
-    // TODO Smaller preview
-    preview->setSize(width, height, width, height);
+    // Smaller preview
+    while (width > 800 and height > 800)
+    {
+        width = width / 2;
+        height = height / 2;
+    }
+    preview->setSize(this->width, this->height, width, height);
 }
 
 CanvasPortion *Canvas::at(int x, int y) const

src/render/software/CanvasPortion.cpp

@@ -8,19 +8,23 @@
 #define CHECK_COORDINATES() assert(x >= 0); \
     assert(x < width); \
     assert(y >= 0); \
-    assert(y < height)
+    assert(y < height); \
+    assert(pixels != NULL)
 
 CanvasPortion::CanvasPortion(CanvasPreview* preview):
     preview(preview)
 {
     width = 1;
     height = 1;
-    pixels = new CanvasPixel[1];
+    pixels = NULL;
 }
 
 CanvasPortion::~CanvasPortion()
 {
-    delete[] pixels;
+    if (pixels)
+    {
+        delete[] pixels;
+    }
 }
 
 int CanvasPortion::getFragmentCount(int x, int y) const
@@ -50,9 +54,16 @@ void CanvasPortion::setSize(int width, int height)
 {
     this->width = width;
     this->height = height;
+}
 
-    delete[] pixels;
+void CanvasPortion::preparePixels()
+{
+    if (pixels)
+    {
+        delete[] pixels;
+    }
     pixels = new CanvasPixel[width * height];
+    clear();
 }
 
 void CanvasPortion::pushFragment(int x, int y, const CanvasFragment &fragment)

src/render/software/CanvasPortion.h

@@ -10,6 +10,8 @@ namespace software {
  * Rectangular portion of a Canvas.
  *
  * Contains the pixels of a canvas region (CanvasPixel).
+ *
+ * Pixels are not allocated until preparePixels is called.
  */
 class SOFTWARESHARED_EXPORT CanvasPortion
 {
@@ -25,6 +27,11 @@ public:
     void clear();
     void setSize(int width, int height);
 
+    /**
+     * Prepare (allocate in memory) the pixels area.
+     */
+    void preparePixels();
+
     /**
      * Add a fragment to the pixel located at (x, y).
      *

src/render/software/CanvasPreview.cpp

@@ -18,6 +18,11 @@ CanvasPreview::CanvasPreview()
     dirty_down = 1;
     dirty_up = -1;
 
+    scaled = false;
+    factor = 1.0;
+    factor_x = 1.0;
+    factor_y = 1.0;
+
     lock = new Mutex();
     profile = new ColorProfile();
 }
@@ -44,6 +49,11 @@ void CanvasPreview::setSize(int real_width, int real_height, int preview_width,
     dirty_down = height;
     dirty_up = -1;
 
+    scaled = (real_width != preview_height or real_height != preview_height);
+    factor_x = (double)real_width / (double)preview_width;
+    factor_y = (double)real_height / (double)preview_height;
+    factor = factor_x * factor_y;
+
     lock->release();
 
     reset();
@@ -94,17 +104,26 @@ void CanvasPreview::updateLive(CanvasLiveClient *client)
 
 void CanvasPreview::pushPixel(int real_x, int real_y, const Color &old_color, const Color &new_color)
 {
+    int x, y;
+
     lock->acquire();
 
-    // TODO Assert-check and transform coordinates
-    int x = real_x;
-    int y = real_y;
-    double fact = 1.0;
+    // TODO Assert-check
+    if (scaled)
+    {
+        x = round(real_x / factor_x);
+        y = round(real_y / factor_y);
+    }
+    else
+    {
+        x = real_x;
+        y = real_y;
+    }
 
-    Color* pixel = pixels + (real_y * width + real_x);
-    pixel->r = pixel->r - old_color.r * fact + new_color.r * fact;
-    pixel->g = pixel->g - old_color.g * fact + new_color.g * fact;
-    pixel->b = pixel->b - old_color.b * fact + new_color.b * fact;
+    Color* pixel = pixels + (y * width + x);
+    pixel->r = pixel->r - old_color.r / factor + new_color.r / factor;
+    pixel->g = pixel->g - old_color.g / factor + new_color.g / factor;
+    pixel->b = pixel->b - old_color.b / factor + new_color.b / factor;
 
     // Set pixel dirty
     if (x < dirty_left)

src/render/software/CanvasPreview.h

@@ -42,6 +42,11 @@ private:
     int dirty_right;
     int dirty_down;
     int dirty_up;
+
+    bool scaled;
+    double factor;
+    double factor_x;
+    double factor_y;
 };
 
 }

src/render/software/SoftwareCanvasRenderer.cpp

@@ -43,7 +43,6 @@ void SoftwareCanvasRenderer::render()
 {
     // TEMP
     started = true;
-    CanvasPortion *portion = canvas->at(0, 0);
     render_width = canvas->getWidth();
     render_height = canvas->getHeight();
     render_quality = 3;
@@ -52,6 +51,9 @@ void SoftwareCanvasRenderer::render()
 
     prepare();
 
+    // TODO Iterate portions
+    CanvasPortion *portion = canvas->at(0, 0);
+    portion->preparePixels();
     rasterize(portion, true);
     postProcess(portion, true);
 }