Add support for scaling to _stage

On high-resolution displays we can use 2x2 or even 3x3 pixels.

3 files changed, 31 insertions, 20 deletions

diff --git a/shared-bindings/_stage/__init__.c b/shared-bindings/_stage/__init__.c
index 1ca206339..485fa80c5 100644
--- a/shared-bindings/_stage/__init__.c
+++ b/shared-bindings/_stage/__init__.c
@@ -50,7 +50,7 @@
 //|     Layer
 //|     Text
 //|
-//| .. function:: render(x0, y0, x1, y1, layers, buffer, display)
+//| .. function:: render(x0, y0, x1, y1, layers, buffer, display[, scale])
 //|
 //|     Render and send to the display a fragment of the screen.
 //|
@@ -61,6 +61,7 @@
 //|     :param list layers: A list of the :py:class:`~_stage.Layer` objects.
 //|     :param bytearray buffer: A buffer to use for rendering.
 //|     :param ~displayio.Display display: The display to use.
+//|     :param int scale: How many times should the image be scaled up.
 //|
 //|     There are also no sanity checks, outside of the basic overflow
 //|     checking. The caller is responsible for making the passed parameters
@@ -89,6 +90,10 @@ STATIC mp_obj_t stage_render(size_t n_args, const mp_obj_t *args) {
         mp_raise_TypeError(translate("argument num/types mismatch"));
     }
     displayio_display_obj_t *display = MP_OBJ_TO_PTR(native_display);
+    uint8_t scale = 1;
+    if (n_args >= 8) {
+        scale = mp_obj_get_int(args[7]);
+    }
 
     while (!displayio_display_begin_transaction(display)) {
 #ifdef MICROPY_VM_HOOK_LOOP
@@ -103,12 +108,13 @@ STATIC mp_obj_t stage_render(size_t n_args, const mp_obj_t *args) {
     displayio_display_set_region_to_update(display, &area);
 
     display->send(display->bus, true, &display->write_ram_command, 1);
-    render_stage(x0, y0, x1, y1, layers, layers_size, buffer, buffer_size, display);
+    render_stage(x0, y0, x1, y1, layers, layers_size, buffer, buffer_size,
+                 display, scale);
     displayio_display_end_transaction(display);
 
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(stage_render_obj, 7, 7, stage_render);
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(stage_render_obj, 7, 8, stage_render);
 
 
 STATIC const mp_rom_map_elem_t stage_module_globals_table[] = {
diff --git a/shared-module/_stage/__init__.c b/shared-module/_stage/__init__.c
index 1af279e92..ca71b758e 100644
--- a/shared-module/_stage/__init__.c
+++ b/shared-module/_stage/__init__.c
@@ -34,30 +34,35 @@
 void render_stage(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1,
         mp_obj_t *layers, size_t layers_size,
         uint16_t *buffer, size_t buffer_size,
-        displayio_display_obj_t *display) {
+        displayio_display_obj_t *display, uint8_t scale) {
 
     size_t index = 0;
     for (uint16_t y = y0; y < y1; ++y) {
-        for (uint16_t x = x0; x < x1; ++x) {
-            for (size_t layer = 0; layer < layers_size; ++layer) {
+        for (uint8_t yscale = 0; yscale < scale; ++yscale) {
+            for (uint16_t x = x0; x < x1; ++x) {
                 uint16_t c = TRANSPARENT;
-                layer_obj_t *obj = MP_OBJ_TO_PTR(layers[layer]);
-                if (obj->base.type == &mp_type_layer) {
-                    c = get_layer_pixel(obj, x, y);
-                } else if (obj->base.type == &mp_type_text) {
-                    c = get_text_pixel((text_obj_t *)obj, x, y);
+                for (size_t layer = 0; layer < layers_size; ++layer) {
+                    layer_obj_t *obj = MP_OBJ_TO_PTR(layers[layer]);
+                    if (obj->base.type == &mp_type_layer) {
+                        c = get_layer_pixel(obj, x, y);
+                    } else if (obj->base.type == &mp_type_text) {
+                        c = get_text_pixel((text_obj_t *)obj, x, y);
+                    }
+                    if (c != TRANSPARENT) {
+                        break;
+                    }
                 }
-                if (c != TRANSPARENT) {
+                for (uint8_t xscale = 0; xscale < scale; ++xscale) {
                     buffer[index] = c;
-                    break;
+                    index += 1;
+                    // The buffer is full, send it.
+                    if (index >= buffer_size) {
+                        display->send(display->bus, false, ((uint8_t*)buffer),
+                                      buffer_size * 2);
+                        index = 0;
+                    }
                 }
             }
-            index += 1;
-            // The buffer is full, send it.
-            if (index >= buffer_size) {
-                display->send(display->bus, false, ((uint8_t*)buffer), buffer_size * 2);
-                index = 0;
-            }
         }
     }
     // Send the remaining data.
diff --git a/shared-module/_stage/__init__.h b/shared-module/_stage/__init__.h
index d263302b4..5af2124ae 100644
--- a/shared-module/_stage/__init__.h
+++ b/shared-module/_stage/__init__.h
@@ -37,6 +37,6 @@
 void render_stage(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1,
         mp_obj_t *layers, size_t layers_size,
         uint16_t *buffer, size_t buffer_size,
-        displayio_display_obj_t *display);
+        displayio_display_obj_t *display, uint8_t scale);
 
 #endif  // MICROPY_INCLUDED_SHARED_MODULE__STAGE