lib: Introduce libgfx

This commit introduces libgfx which is a low-level graphics library
and does not know anything about windows, display architecture, etc.
The job of libgfx is soley to provide an API to draw shapes, graphical objects
and perform operations on them.

Signed-off-by: Ian Moffett <ian@osmora.org>

2 files changed, 193 insertions, 0 deletions

diff --git a/lib/libgfx/src/draw.c b/lib/libgfx/src/draw.c
new file mode 100644
index 0000000..49f2f53
--- /dev/null
+++ b/lib/libgfx/src/draw.c
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/errno.h>
+#include <stdint.h>
+#include <libgfx/gfx.h>
+#include <libgfx/draw.h>
+
+/*
+ * Draw a classic square onto the screen.
+ *
+ * @ctx: Graphics context
+ * @shape: Square to draw
+ */
+static int
+gfx_draw_square(struct gfx_ctx *ctx, const struct gfx_shape *shape)
+{
+    struct fbattr fbdev;
+    off_t idx;
+    scrpos_t scr_width, scr_height;
+    scrpos_t x, y;
+
+    if (ctx == NULL || shape == NULL) {
+        return -EINVAL;
+    }
+
+    /* Grab screen dimensions */
+    fbdev = ctx->fbdev;
+    scr_width = fbdev.width;
+    scr_height = fbdev.height;
+
+    for (x = shape->x; x < shape->x + shape->width; ++x) {
+        for (y = shape->y; y < shape->y + shape->height; ++y) {
+            if (x >= scr_width || y >= scr_height) {
+                break;
+            }
+
+            idx = gfx_io_index(ctx, x, y);
+            ctx->io[idx] = shape->color;
+        }
+    }
+    return 0;
+}
+
+/*
+ * Draw a shape onto the screen
+ *
+ * @ctx: libgfx graphics context
+ * @shape: Shape to draw
+ *
+ * Returns 0 on success, otherwise a less than zero
+ * value on failure.
+ *
+ * All error codes follow POSIX errno. However if the value
+ * is -1, the requested shape to be drawn is not valid.
+ */
+int
+gfx_draw_shape(struct gfx_ctx *ctx, const struct gfx_shape *shape)
+{
+    if (ctx == NULL || shape == NULL) {
+        return -EINVAL;
+    }
+
+    switch (shape->type) {
+    case SHAPE_SQUARE:
+        return gfx_draw_square(ctx, shape);
+    }
+
+    return -1;
+}
diff --git a/lib/libgfx/src/gfx.c b/lib/libgfx/src/gfx.c
new file mode 100644
index 0000000..90dcb79
--- /dev/null
+++ b/lib/libgfx/src/gfx.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/errno.h>
+#include <sys/mman.h>
+#include <sys/fbdev.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <libgfx/gfx.h>
+
+/*
+ * Initialize the libgfx context
+ *
+ * @res: Context pointer to be initialized
+ */
+int
+gfx_init(struct gfx_ctx *res)
+{
+    struct fbattr attr;
+    int fd, prot;
+
+    if (res == NULL) {
+        return -EINVAL;
+    }
+
+    /* Get framebuffer attributes */
+    fd = open("/ctl/fb0/attr", O_RDONLY);
+    if (fd < 0) {
+        gfx_log("could not open '/ctl/fb0/attr");
+        return fd;
+    }
+
+    read(fd, &attr, sizeof(attr));
+    close(fd);
+    res->fbdev = attr;
+
+    /* Open the framebuffer file */
+    res->fbfd = open("/dev/fb0", O_RDWR);
+    if (res->fbfd < 0) {
+        gfx_log("could not open '/dev/fb0'\n");
+        return res->fbfd;
+    }
+
+    /* Map the framebuffer into memory */
+    prot = PROT_READ | PROT_WRITE;
+    res->fb_size = attr.height * attr.pitch;
+    res->io = mmap(NULL, res->fb_size, prot, MAP_SHARED, res->fbfd, 0);
+
+    /* Did the mmap() call work? */
+    if (res->io == NULL) {
+        gfx_log("could not map framebuffer\n");
+        close(res->fbfd);
+        return -1;
+    }
+
+    return 0;
+}
+
+/*
+ * Cleanup all state and free the gfx
+ * context.
+ */
+void
+gfx_cleanup(struct gfx_ctx *ctx)
+{
+    if (ctx->io != NULL)
+        munmap(ctx->io, ctx->fb_size);
+    if (ctx->fbfd > 0)
+        close(ctx->fbfd);
+}