Merge pull request #52 from gridpoint-com/jringle/cairo-gtk

Cairo support, part 3 of 3.

Makefile

@@ -64,6 +64,7 @@ NVG_COMMON_SRCS = \
 	c_src/device/nvg/nvg_script_ops.c
 
 CAIRO_COMMON_SRCS = \
+	c_src/device/cairo/cairo_common.c \
 	c_src/device/cairo/cairo_font_ops.c \
 	c_src/device/cairo/cairo_image_ops.c \
 	c_src/device/cairo/cairo_script_ops.c
@@ -143,6 +144,16 @@ else ifeq ($(SCENIC_LOCAL_TARGET),cairo-fb)
 		$(CAIRO_COMMON_SRCS) \
 		c_src/device/cairo/cairo_fb.c
 
+else ifeq ($(SCENIC_LOCAL_TARGET),cairo-gtk)
+	LDFLAGS += `pkg-config --static --libs freetype2 cairo gtk+-3.0`
+	CFLAGS += `pkg-config --static --cflags freetype2 cairo gtk+-3.0`
+	LDFLAGS += -lm
+	CFLAGS ?= -O2 -Wall -Wextra -Wno-unused-parameter -pedantic
+	CFLAGS += -std=gnu99
+
+	DEVICE_SRCS += \
+		$(CAIRO_COMMON_SRCS) \
+		c_src/device/cairo/cairo_gtk.c
 else
 $(info ------ no SCENIC_LOCAL_TARGET set ------)
 $(info If you get here, then you are probably using a custom Nerves system)

README.md

@@ -43,11 +43,18 @@ For example, for apps running on a Mac/PC/Linux, it is usually set to `host`, wh
 
 If you are building for Nerves, it will use `bcm` (Broadcom Manager) for any of `rpi`, `rpi0`, `rip2`, `rpi3`, and `rpi3a`.
 
+### Cairo
+There is now a rendering backend to use `cairo`. You can set SCENIC_LOCAL_TARGET to `cairo-fb` which renders to `/dev/fb0` on an embedded device or `cairo-gtk` which renders to a window on a host (as an alternative to `glfw`).
+
+`cairo-fb` will require that your `nerves_system_*` has the `cairo` library selected.
+
 ### Nerves rpi4 & bbb Need Work / Help
 `Scenic.Driver.Local` uses `drm` (Direct Render Manager) for the `rpi4` and `bbb`. It currently renders on the rpi4, but is __very slow__. I haven't figured out why yet and if anyone wants to dig in, that would be appreciated. It should be really fast, so is probably a hardware configuration issue.
 
 The `bbb` doesn't work (is close in theory??) as the Nerves `bbb` system doesn't have the needed graphics support in it yet. There are others who have gotten SGX support working for the `bbb` and I could use some help from them.
 
+Please try using `cairo-fb` to see if it will work for you on `rpi4` or `bbb`.
+
 ### Custom Nerves Targets
 For custom systems (example - figuring out how to add SGX support to the `bbb`) You will need to set SCENIC_LOCAL_TARGET manually. You may also need to set the SCENIC_LOCAL_GL as well.
 
@@ -92,11 +99,18 @@ Once these components have been installed, you should be able to build the `scen
 
 The easiest way to install on Ubuntu is to use apt-get. Just run the following:
 
+For `glfw`:
 ```bash
 apt-get update
 apt-get install pkgconf libglfw3 libglfw3-dev libglew2.1 libglew-dev
 ```
 
+For `cairo-gtk`:
+```bash
+apt-get update
+apt-get install pkgconf libgtk-3-0 libgtk-3-dev libsystemd-dev libwebp-dev libzstd-dev
+```
+
 Once these components have been installed, you should be able to build the `scenic_driver_local` driver.
 
 ### Installing on Arch Linux

c_src/device/cairo/cairo_common.c

@@ -0,0 +1,99 @@
+#include "cairo_ctx.h"
+#include "device.h"
+
+extern device_info_t g_device_info;
+
+scenic_cairo_ctx_t* scenic_cairo_init(const device_opts_t* p_opts,
+                                      device_info_t* p_info)
+{
+  scenic_cairo_ctx_t* p_ctx = calloc(1, sizeof(scenic_cairo_ctx_t));
+
+  FT_Error status = FT_Init_FreeType(&p_ctx->ft_library);
+  if (status != 0) {
+    log_error("cairo: FT_Init_FreeType: Error: %d", status);
+    free(p_ctx);
+
+    return NULL;
+  }
+
+  p_ctx->ratio = 1.0f;
+  p_ctx->dist_tolerance = 0.1f * p_ctx->ratio;
+
+  p_info->width = p_opts->width;
+  p_info->height = p_opts->height;
+
+  p_ctx->font_size = 10.0; // Cairo default
+  p_ctx->text_align = TEXT_ALIGN_LEFT;
+  p_ctx->text_base = TEXT_BASE_ALPHABETIC;
+
+  p_ctx->clear_color = (color_rgba_t){
+    // black opaque
+    .red = 0.0,
+    .green = 0.0,
+    .blue = 0.0,
+    .alpha = 1.0
+  };
+
+  p_info->v_ctx = p_ctx;
+
+  p_ctx->surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
+                                              p_info->width, p_info->height);
+
+  return p_ctx;
+}
+
+void scenic_cairo_fini(scenic_cairo_ctx_t* p_ctx)
+{
+  cairo_surface_destroy(p_ctx->surface);
+  free(p_ctx);
+}
+
+void device_begin_cursor_render(driver_data_t* p_data)
+{
+  scenic_cairo_ctx_t* p_ctx = (scenic_cairo_ctx_t*)p_data->v_ctx;
+  cairo_translate(p_ctx->cr, p_data->cursor_pos[0], p_data->cursor_pos[1]);
+}
+
+void device_clear_color(float red, float green, float blue, float alpha)
+{
+  scenic_cairo_ctx_t* p_ctx = (scenic_cairo_ctx_t*)g_device_info.v_ctx;
+  p_ctx->clear_color = (color_rgba_t){
+    .red = red,
+    .green = green,
+    .blue = blue,
+    .alpha = alpha
+  };
+}
+
+char* device_gl_error()
+{
+  return NULL;
+}
+
+void pattern_stack_push(scenic_cairo_ctx_t* p_ctx)
+{
+  pattern_stack_t* ptr = (pattern_stack_t*)malloc(sizeof(pattern_stack_t));
+
+  ptr->pattern = p_ctx->pattern;
+
+  if (!p_ctx->pattern_stack_head) {
+    ptr->next = NULL;
+    p_ctx->pattern_stack_head = ptr;
+  } else {
+    ptr->next = p_ctx->pattern_stack_head;
+    p_ctx->pattern_stack_head = ptr;
+  }
+}
+
+void pattern_stack_pop(scenic_cairo_ctx_t* p_ctx)
+{
+  pattern_stack_t* ptr = p_ctx->pattern_stack_head;
+
+  if (!ptr) {
+    log_error("pattern stack underflow");
+  } else {
+    p_ctx->pattern = ptr->pattern;
+    p_ctx->pattern_stack_head = p_ctx->pattern_stack_head->next;
+    free(ptr);
+  }
+}

c_src/device/cairo/cairo_ctx.h

@@ -32,11 +32,6 @@ typedef struct {
   float font_size;
   text_align_t text_align;
   text_base_t text_base;
-  union {
-    u_int8_t  *c;
-    u_int16_t *s;
-    u_int32_t *i;
-  } fbbuff;
   cairo_surface_t* surface;
   cairo_t* cr;
   pattern_stack_t* pattern_stack_head;
@@ -53,6 +48,10 @@ typedef struct {
   float ratio;
 } scenic_cairo_ctx_t;
 
+scenic_cairo_ctx_t* scenic_cairo_init(const device_opts_t* p_opts,
+                                      device_info_t* p_info);
+void scenic_cairo_fini(scenic_cairo_ctx_t* p_ctx);
+
 void pattern_stack_push(scenic_cairo_ctx_t* p_ctx);
 void pattern_stack_pop(scenic_cairo_ctx_t* p_ctx);