From caa3d3726fab4551a275916f6240bbfa26634f4a Mon Sep 17 00:00:00 2001
From: Radomir Dopieralski <openstack@sheep.art.pl>
Date: Sat, 9 Oct 2021 00:05:49 +0200
Subject: [PATCH] Stage: add support for viewport scrolling

---
 frozen/circuitpython-stage        |  2 +-
 shared-bindings/_stage/__init__.c | 16 ++++++----------
 shared-module/_stage/__init__.c   |  9 ++++++---
 shared-module/_stage/__init__.h   |  5 ++++-
 4 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/frozen/circuitpython-stage b/frozen/circuitpython-stage
index 2b9b9f0a80..2c89a32906 160000
--- a/frozen/circuitpython-stage
+++ b/frozen/circuitpython-stage
@@ -1 +1 @@
-Subproject commit 2b9b9f0a80810b0c4ff0feebbbe07312251de144
+Subproject commit 2c89a329063848bcd7dba6af6fb6c9d6036dd4f2
diff --git a/shared-bindings/_stage/__init__.c b/shared-bindings/_stage/__init__.c
index 1d5c06c862..4dfcc796e7 100644
--- a/shared-bindings/_stage/__init__.c
+++ b/shared-bindings/_stage/__init__.c
@@ -81,21 +81,17 @@ 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 > 7) {
-        scale = mp_obj_get_int(args[7]);
-    }
+    uint8_t scale = mp_obj_get_int(args[7]);
+    int16_t vx = mp_obj_get_int(args[8]);
+    int16_t vy = mp_obj_get_int(args[9]);
     uint16_t background = 0;
-    if (n_args > 8) {
-        background = mp_obj_get_int(args[8]);
-    }
 
-    render_stage(x0, y0, x1, y1, layers, layers_size, buffer, buffer_size,
-        display, scale, background);
+    render_stage(x0, y0, x1, y1, vx, vy, layers, layers_size,
+        buffer, buffer_size, display, scale, background);
 
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(stage_render_obj, 7, 8, stage_render);
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(stage_render_obj, 10, 10, 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 69f7812c0e..7ec640bc6e 100644
--- a/shared-module/_stage/__init__.c
+++ b/shared-module/_stage/__init__.c
@@ -31,7 +31,10 @@
 #include "shared-bindings/_stage/Text.h"
 
 
-void render_stage(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1,
+void render_stage(
+    uint16_t x0, uint16_t y0,
+    uint16_t x1, uint16_t y1,
+    int16_t vx, int16_t vy,
     mp_obj_t *layers, size_t layers_size,
     uint16_t *buffer, size_t buffer_size,
     displayio_display_obj_t *display,
@@ -55,9 +58,9 @@ void render_stage(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1,
         CHIP_SELECT_TOGGLE_EVERY_BYTE,
         &display->write_ram_command, 1);
     size_t index = 0;
-    for (uint16_t y = y0; y < y1; ++y) {
+    for (int16_t y = y0 + vy; y < y1 + vy; ++y) {
         for (uint8_t yscale = 0; yscale < scale; ++yscale) {
-            for (uint16_t x = x0; x < x1; ++x) {
+            for (int16_t x = x0 + vx; x < x1 + vx; ++x) {
                 uint16_t c = TRANSPARENT;
                 for (size_t layer = 0; layer < layers_size; ++layer) {
                     layer_obj_t *obj = MP_OBJ_TO_PTR(layers[layer]);
diff --git a/shared-module/_stage/__init__.h b/shared-module/_stage/__init__.h
index 5cbaa235b6..596752bee5 100644
--- a/shared-module/_stage/__init__.h
+++ b/shared-module/_stage/__init__.h
@@ -34,7 +34,10 @@
 
 #define TRANSPARENT (0x1ff8)
 
-void render_stage(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1,
+void render_stage(
+    uint16_t x0, uint16_t y0,
+    uint16_t x1, uint16_t y1,
+    int16_t vx, int16_t vy,
     mp_obj_t *layers, size_t layers_size,
     uint16_t *buffer, size_t buffer_size,
     displayio_display_obj_t *display,