GUAC-236: Flatten and render all layers upon sync.

src/guacenc/display.c

@@ -30,6 +30,7 @@
 #include <guacamole/protocol.h>
 #include <guacamole/timestamp.h>
 
+#include <assert.h>
 #include <inttypes.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -93,20 +94,9 @@ int guacenc_display_sync(guacenc_display* display, guac_timestamp timestamp) {
         return 1;
     }
 
-    /* Get buffer for display frame rendering */
-    guacenc_buffer* frame = display->frame;
-
     /* Update timestamp of display */
     display->last_sync = timestamp;
 
-    /* Ensure frame is the same size as the default layer */
-    guacenc_buffer* def_layer = guacenc_display_get_related_buffer(display, 0);
-    guacenc_buffer_resize(frame, def_layer->width, def_layer->height);
-
-    /* Render all layers to frame */
-    cairo_t* cairo = frame->cairo;
-    if (cairo != NULL) {
-
     int i;
     guacenc_layer* render_order[GUACENC_DISPLAY_MAX_LAYERS];
 
@@ -118,6 +108,23 @@ int guacenc_display_sync(guacenc_display* display, guac_timestamp timestamp) {
     qsort(render_order, GUACENC_DISPLAY_MAX_LAYERS, sizeof(guacenc_layer*),
             guacenc_display_layer_comparator);
 
+    /* Reset layer frame buffers */
+    for (i = 0; i < GUACENC_DISPLAY_MAX_LAYERS; i++) {
+
+        /* Pull current layer, ignoring unallocated layers */
+        guacenc_layer* layer = render_order[i];
+        if (layer == NULL)
+            continue;
+
+        /* Get source buffer and destination frame buffer */
+        guacenc_buffer* buffer = layer->buffer;
+        guacenc_buffer* frame = layer->frame;
+
+        /* Reset frame contents */
+        guacenc_buffer_copy(frame, buffer);
+
+    }
+
     /* Render each layer, in order */
     for (i = 0; i < GUACENC_DISPLAY_MAX_LAYERS; i++) {
 
@@ -130,33 +137,48 @@ int guacenc_display_sync(guacenc_display* display, guac_timestamp timestamp) {
         if (layer->opacity == 0)
             continue;
 
-            /* Pull underlying buffer */
+        /* Ignore layers without a parent */
-            guacenc_buffer* buffer = layer->buffer;
+        int parent_index = layer->parent_index;
-
+        if (parent_index == GUACENC_LAYER_NO_PARENT)
-            /* Ignore layers with empty buffers */
-            if (buffer->surface == NULL)
             continue;
 
-            /* TODO: Determine actual location relative to parent layer */
+        /* Retrieve parent layer, ignoring layers with invalid parents */
-            int x = layer->x;
+        guacenc_layer* parent = guacenc_display_get_layer(display, parent_index);
-            int y = layer->y;
+        if (parent == NULL)
+            continue;
+
+        /* Get source and destination frame buffer */
+        guacenc_buffer* src = layer->frame;
+        guacenc_buffer* dst = parent->frame;
+
+        /* Ignore layers with empty buffers */
+        cairo_surface_t* surface = src->surface;
+        if (surface == NULL)
+            continue;
+
+        /* Ignore if parent has no pixels */
+        cairo_t* cairo = dst->cairo;
+        if (cairo == NULL)
+            continue;
 
         /* Render buffer to layer */
         cairo_reset_clip(cairo);
-            cairo_rectangle(cairo, x, y, buffer->width, buffer->height);
+        cairo_rectangle(cairo, layer->x, layer->y, src->width, src->height);
         cairo_clip(cairo);
 
-            cairo_set_source_surface(cairo, buffer->surface, x, y);
+        cairo_set_source_surface(cairo, surface, layer->x, layer->y);
         cairo_paint_with_alpha(cairo, layer->opacity / 255.0);
 
     }
 
-    }
+    /* Retrieve default layer (guaranteed to not be NULL) */
+    guacenc_layer* def_layer = guacenc_display_get_layer(display, 0);
+    assert(def_layer != NULL);
 
     /* STUB: Write frame as PNG */
     char filename[256];
     sprintf(filename, "frame-%" PRId64 ".png", timestamp);
-    cairo_surface_t* surface = frame->surface;
+    cairo_surface_t* surface = def_layer->frame->surface;
     if (surface != NULL)
         cairo_surface_write_to_png(surface, filename);
 
@@ -424,16 +446,7 @@ cairo_operator_t guacenc_display_cairo_operator(guac_composite_mode mask) {
 }
 
 guacenc_display* guacenc_display_alloc() {
-
+    return (guacenc_display*) calloc(1, sizeof(guacenc_display));
-    /* Allocate display */
-    guacenc_display* display =
-        (guacenc_display*) calloc(1, sizeof(guacenc_display));
-
-    /* Allocate buffer for frame rendering */
-    display->frame = guacenc_buffer_alloc();
-
-    return display;
-
 }
 
 int guacenc_display_free(guacenc_display* display) {
@@ -444,9 +457,6 @@ int guacenc_display_free(guacenc_display* display) {
     if (display == NULL)
         return 0;
 
-    /* Free internal frame buffer */
-    guacenc_buffer_free(display->frame);
-
     /* Free all buffers */
     for (i = 0; i < GUACENC_DISPLAY_MAX_BUFFERS; i++)
         guacenc_buffer_free(display->buffers[i]);

src/guacenc/display.h

@@ -84,12 +84,6 @@ typedef struct guacenc_display {
      */
     guac_timestamp last_sync;
 
-    /**
-     * The internal buffer used by the display to record the previous frame
-     * and to render additional frames.
-     */
-    guacenc_buffer* frame;
-
 } guacenc_display;
 
 /**