arch(draw): allow replacing the draw engine

BREAKING CHANGE: the API of lv_draw_... function have been changed

src/draw/sdl/lv_draw_sdl_line.c

@@ -0,0 +1,151 @@
+/**
+ * @file lv_templ.c
+ *
+ */
+
+/*********************
+ *      INCLUDES
+ *********************/
+#include "../../lv_conf_internal.h"
+
+#if LV_USE_GPU_SDL
+
+#include "lv_draw_sdl.h"
+#include "lv_draw_sdl_utils.h"
+#include "lv_draw_sdl_texture_cache.h"
+#include "lv_draw_sdl_composite.h"
+#include "lv_draw_sdl_mask.h"
+
+/*********************
+ *      DEFINES
+ *********************/
+#define ROUND_START 0x01
+#define ROUND_END 0x02
+/**********************
+ *      TYPEDEFS
+ **********************/
+
+typedef struct {
+    lv_sdl_cache_key_magic_t magic;
+    lv_coord_t length;
+    lv_coord_t width;
+    uint8_t round;
+} lv_draw_line_key_t;
+
+/**********************
+ *  STATIC PROTOTYPES
+ **********************/
+
+/**********************
+ *  STATIC VARIABLES
+ **********************/
+
+/**********************
+ *      MACROS
+ **********************/
+
+static lv_draw_line_key_t line_key_create(const lv_draw_line_dsc_t * dsc, lv_coord_t length);
+
+static SDL_Texture * line_texture_create(lv_draw_sdl_ctx_t * sdl_ctx, const lv_draw_line_dsc_t * dsc,
+                                         lv_coord_t length);
+
+/**********************
+ *   GLOBAL FUNCTIONS
+ **********************/
+void lv_draw_sdl_draw_line(lv_draw_ctx_t * draw_ctx, const lv_draw_line_dsc_t * dsc, const lv_point_t * point1,
+                           const lv_point_t * point2)
+{
+    lv_draw_sdl_ctx_t * sdl_ctx = (lv_draw_sdl_ctx_t *) draw_ctx;
+    SDL_Renderer * renderer = sdl_ctx->renderer;
+    lv_coord_t x1 = point1->x, x2 = point2->x, y1 = point1->y, y2 = point2->y;
+    double length = SDL_sqrt(SDL_pow(x2 - x1, 2) + SDL_pow(y2 - y1, 2));
+    if(length - (long) length > 0.5) {
+        length = (long) length + 1;
+    }
+
+    double angle = SDL_atan2(y2 - y1, x2 - x1) * 180 / M_PI;
+    lv_draw_line_key_t key = line_key_create(dsc, length);
+    SDL_Texture * texture = lv_draw_sdl_texture_cache_get(sdl_ctx, &key, sizeof(key), NULL);
+    if(!texture) {
+        texture = line_texture_create(sdl_ctx, dsc, length);
+        lv_draw_sdl_texture_cache_put(sdl_ctx, &key, sizeof(key), texture);
+    }
+
+    lv_area_t coords = {x1, y1, x2, y2};
+    const lv_area_t * clip = draw_ctx->clip_area;
+
+    SDL_Rect coords_r, clip_r;
+    lv_area_to_sdl_rect(&coords, &coords_r);
+    lv_area_to_sdl_rect(clip, &clip_r);
+
+    lv_area_t t_coords = coords, t_clip = *clip, apply_area;
+    lv_area_t extension = {dsc->width / 2, dsc->width / 2, dsc->width / 2, dsc->width / 2};
+    bool has_mask = lv_draw_sdl_composite_begin(sdl_ctx, &coords, clip, &extension, dsc->blend_mode, &t_coords, &t_clip,
+                                                &apply_area);
+
+    SDL_Color color;
+    lv_color_to_sdl_color(&dsc->color, &color);
+
+    SDL_Rect clip_rect;
+    lv_area_to_sdl_rect(&t_clip, &clip_rect);
+    SDL_RenderSetClipRect(renderer, &clip_rect);
+    SDL_SetTextureColorMod(texture, color.r, color.g, color.b);
+    SDL_SetTextureAlphaMod(texture, dsc->opa);
+    SDL_Rect srcrect = {0, 0, length + dsc->width + 2, dsc->width + 2},
+             dstrect = {t_coords.x1 - 1 - dsc->width / 2, t_coords.y1 - 1, srcrect.w, srcrect.h};
+    SDL_Point center = {1 + dsc->width / 2, 1 + dsc->width / 2};
+    SDL_RenderCopyEx(renderer, texture, &srcrect, &dstrect, angle, &center, 0);
+    SDL_RenderSetClipRect(renderer, NULL);
+
+    lv_draw_sdl_composite_end(sdl_ctx, &apply_area, dsc->blend_mode);
+}
+
+/**********************
+ *   STATIC FUNCTIONS
+ **********************/
+
+static lv_draw_line_key_t line_key_create(const lv_draw_line_dsc_t * dsc, lv_coord_t length)
+{
+    lv_draw_line_key_t key;
+    lv_memset_00(&key, sizeof(lv_draw_line_key_t));
+    key.magic = LV_GPU_CACHE_KEY_MAGIC_LINE;
+    key.length = length;
+    key.width = dsc->width;
+    key.round = (dsc->round_start ? ROUND_START : 0) | (dsc->round_end ? ROUND_END : 0);
+    return key;
+}
+
+static SDL_Texture * line_texture_create(lv_draw_sdl_ctx_t * sdl_ctx, const lv_draw_line_dsc_t * dsc, lv_coord_t length)
+{
+    SDL_Texture * texture = SDL_CreateTexture(sdl_ctx->renderer, LV_DRAW_SDL_TEXTURE_FORMAT, SDL_TEXTUREACCESS_TARGET,
+                                              length + dsc->width + 2, dsc->width + 2);
+    SDL_Texture * target = SDL_GetRenderTarget(sdl_ctx->renderer);
+    SDL_SetRenderTarget(sdl_ctx->renderer, texture);
+    SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
+    SDL_SetRenderDrawColor(sdl_ctx->renderer, 0xFF, 0xFF, 0xFF, 0x0);
+    SDL_RenderClear(sdl_ctx->renderer);
+    SDL_SetRenderDrawColor(sdl_ctx->renderer, 0xFF, 0xFF, 0xFF, 0xFF);
+    SDL_Rect line_rect = {1 + dsc->width / 2, 1, length, dsc->width};
+    SDL_RenderFillRect(sdl_ctx->renderer, &line_rect);
+    if(dsc->round_start || dsc->round_end) {
+        lv_draw_mask_radius_param_t param;
+        lv_area_t round_area = {0, 0, dsc->width - 1, dsc->width - 1};
+        lv_draw_mask_radius_init(&param, &round_area, LV_RADIUS_CIRCLE, false);
+
+        int16_t mask_id = lv_draw_mask_add(&param, NULL);
+        SDL_Texture * round_texture = lv_draw_sdl_mask_dump_texture(sdl_ctx->renderer, &round_area, &mask_id, 1);
+        lv_draw_mask_remove_id(mask_id);
+
+        SDL_Rect round_src = {0, 0, dsc->width, dsc->width};
+        SDL_Rect round_dst = {line_rect.x - dsc->width / 2, 1, dsc->width, dsc->width};
+        SDL_RenderCopy(sdl_ctx->renderer, round_texture, &round_src, &round_dst);
+        round_dst.x = line_rect.w + dsc->width / 2;
+        SDL_RenderCopy(sdl_ctx->renderer, round_texture, &round_src, &round_dst);
+        SDL_DestroyTexture(round_texture);
+    }
+
+    SDL_SetRenderTarget(sdl_ctx->renderer, target);
+    return texture;
+}
+
+#endif /*LV_USE_GPU_SDL*/