根据文章： Linux下支持AX206 LCD FOR AIDA64 Business ，可以实现输出png图片到AX206 LCD。那么如果我们想输出framebuffer的图像到LCD屏幕呢？如何实现？
根据[email protected]:ukoda/lcd4linux-ax206.git仓库的代码，我们可以看到png图片的渲染是通过widget_image.c中的 static void widget_image_render(const char *Name, WIDGET_IMAGE * Image) 函数实现的。
我们可以通过如下修改，实现输出framebuffer图像到AX206 LCD的效果：
diff --git a/contrib/picoLCD/dpf_480_320.conf b/contrib/picoLCD/dpf_480_320.conf
new file mode 100644
index 0000000..34e6b51
--- /dev/null
+++ b/contrib/picoLCD/dpf_480_320.conf
@@ -0,0 +1,42 @@
+Display dpf {
+ Driver 'DPF'
+ Port 'usb0'
+ Font '6x8'
+ Foreground 'ffffff'
+ Background '000000'
+ Basecolor '000000'
+ Orientation 0 # 0 = landscape, 1 = portrait
+ # 2 = reverse landscape, 3 = reverse portrait
+ Backlight backlight # Backlight variable control, 0..7 (0=off, 7=max)
+}
+
+Widget Bgnd {
+ class 'Image'
+ file '/dev/fb1'
+ reload 1
+ update 1000
+ inverted 0
+ visible 1
+ fb_width 480
+ fb_height 320
+ fb_bpp 32
+}
+
+Display 'DPF'
+
+Layout layout_480x320 {
+ Layer 2 {
+ X1.Y1 'Bgnd'
+ }
+}
+
+Layout 'layout_480x320'
+
+Variables {
+ backlight 7
+ tick 500
+ tack 200
+ minute 60000
+}
+
+
diff --git a/widget_image.c b/widget_image.c
index accabfe..2238731 100644
--- a/widget_image.c
+++ b/widget_image.c
@@ -38,6 +38,10 @@
#include <string.h>
#include <ctype.h>
#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
#ifdef HAVE_GD_GD_H
#include <gd/gd.h>
@@ -69,6 +73,111 @@
#include <dmalloc.h>
#endif
+static int obtain_frame_from_framebuffer(unsigned char *frame_buf,
+ char *fb_dev, int width, int height, int bpp)
+{
+ int fb_fd = open(fb_dev, O_RDWR);
+ if (fb_fd < 0) {
+ error("open dev %s failed", fb_dev);
+ return -1;
+ }
+
+ int nread = read(fb_fd, frame_buf, width*height*bpp);
+ if (nread <= 0) {
+ error("read failed from framebuffer:%d", nread);
+ close(fb_fd);
+ return -1;
+ }
+
+ close(fb_fd);
+ return 0;
+}
+
+static gdImagePtr createImageFromRgb32(unsigned char *rgbData, int width, int height)
+{
+ gdImagePtr im;
+ int x, y;
+ int color;
+
+ im = gdImageCreateTrueColor(width, height);
+ if (!im) {
+ error("Could not create image.\n");
+ return NULL;
+ }
+
+ for (y = 0; y < height; y++) {
+ for (x = 0; x < width; x++) {
+ int index = (y * width + x) * 4;
+
+ unsigned char b = rgbData[index];
+ unsigned char g = rgbData[index + 1];
+ unsigned char r = rgbData[index + 2];
+
+ color = gdImageColorAllocate(im, r, g, b);
+
+ gdImageSetPixel(im, x, y, color);
+ }
+ }
+
+ return im;
+}
+
+static gdImagePtr createImageFromRgb24(unsigned char *rgbData, int width, int height)
+{
+ gdImagePtr im;
+ int x, y;
+ int color;
+
+ im = gdImageCreateTrueColor(width, height);
+ if (!im) {
+ error("Could not create image.\n");
+ return NULL;
+ }
+
+ for (y = 0; y < height; y++) {
+ for (x = 0; x < width; x++) {
+ int index = (y * width + x) * 3;
+
+ unsigned char r = rgbData[index];
+ unsigned char g = rgbData[index + 1];
+ unsigned char b = rgbData[index + 2];
+
+ color = gdImageColorAllocate(im, r, g, b);
+
+ gdImageSetPixel(im, x, y, color);
+ }
+ }
+
+ return im;
+}
+
+static int create_image_from_framebuffer(char *dev_fb, WIDGET_IMAGE *Image)
+{
+ int width, height, Bpp;
+ int retval;
+
+ width = P2N(&Image->fb_width);
+ height = P2N(&Image->fb_height);
+ Bpp = P2N(&Image->fb_bpp) / 8;
+ unsigned char img_buf[width*height*Bpp];
+
+ /* we only support rgba and rgb current */
+ if (width <= 0 || height <= 0 || (Bpp != 4 && Bpp != 3))
+ return -1;
+
+ retval = obtain_frame_from_framebuffer(img_buf, dev_fb, width, height, Bpp);
+ if (retval)
+ return -1;
+
+ if (Bpp == 4)
+ Image->gdImage = createImageFromRgb32(img_buf, width, height);
+ else if (Bpp == 3)
+ Image->gdImage = createImageFromRgb24(img_buf, width, height);
+ else
+ return -1;
+
+ return 0;
+}
static void widget_image_render(const char *Name, WIDGET_IMAGE * Image)
{
@@ -105,13 +214,22 @@ static void widget_image_render(const char *Name, WIDGET_IMAGE * Image)
return;
}
- fd = fopen(file, "rb");
- if (fd == NULL) {
- error("Warning: Image %s: fopen(%s) failed: %s", Name, file, strerror(errno));
- return;
- }
- Image->gdImage = gdImageCreateFromPng(fd);
- fclose(fd);
+ char *f_ptr = strstr(file, "/dev/fb");
+ if (f_ptr) {
+ int retval = create_image_from_framebuffer(file, Image);
+ if (retval) {
+ error("Warning: get frame from %s failed", file);
+ return;
+ }
+ } else {
+ fd = fopen(file, "rb");
+ if (fd == NULL) {
+ error("Warning: Image %s: fopen(%s) failed: %s", Name, file, strerror(errno));
+ return;
+ }
+ Image->gdImage = gdImageCreateFromPng(fd);
+ fclose(fd);
+ }
if (Image->gdImage == NULL) {
fd = fopen(file, "rb");
@@ -293,6 +411,9 @@ static void widget_image_update(void *Self)
property_eval(&Image->visible);
property_eval(&Image->inverted);
property_eval(&Image->center);
+ property_eval(&Image->fb_width);
+ property_eval(&Image->fb_height);
+ property_eval(&Image->fb_bpp);
/* render image into bitmap */
widget_image_render(W->name, Image);
@@ -343,6 +464,9 @@ int widget_image_init(WIDGET * Self)
property_load(section, "visible", "1", &Image->visible);
property_load(section, "inverted", "0", &Image->inverted);
property_load(section, "center", "0", &Image->center);
+ property_load(section, "fb_width", "480", &Image->fb_width);
+ property_load(section, "fb_height", "320", &Image->fb_height);
+ property_load(section, "fb_bpp", "32", &Image->fb_bpp);
/* sanity checks */
if (!property_valid(&Image->file)) {
@@ -389,6 +513,10 @@ int widget_image_quit(WIDGET * Self)
property_free(&Image->visible);
property_free(&Image->inverted);
property_free(&Image->center);
+ property_free(&Image->fb_width);
+ property_free(&Image->fb_height);
+ property_free(&Image->fb_bpp);
+
free(Self->data);
Self->data = NULL;
}
diff --git a/widget_image.h b/widget_image.h
index 6ead2b4..4d64a9a 100644
--- a/widget_image.h
+++ b/widget_image.h
@@ -46,6 +46,9 @@ typedef struct WIDGET_IMAGE {
PROPERTY visible; /* image visible? */
PROPERTY inverted; /* image inverted? */
PROPERTY center; /* image centered? */
+ PROPERTY fb_width; /* size of the framebuffer width */
+ PROPERTY fb_height; /* size of the framebuffer height */
+ PROPERTY fb_bpp; /* bits per pixel */
} WIDGET_IMAGE;
extern WIDGET_CLASS Widget_Image;
如上述修改所示，我们可以通过配置文件dpf_480_320.conf里Bgnd widget的文件名参数 file 来指定要使用哪个framebuffer设备。想要使用fb0就配置file为“/dev/fb0”， 想使用fb1就配置为"/dev/fb1"。这样可以兼容输出png图片到LCD的功能。
配置文件解析：
- dpf_480_320.conf里Bgnd widget的fb_width和fb_height分别表示AX206 LCD分辨率的宽和高。
- dpf_480_320.conf里Bgnd widget的fb_bpp参数根据你系统内framebuffer的bpp(bits per pixel)来决定。
-
- 如果framebuffer的bpp为32(RGBA)， 则fb_bpp参数配置为32。如果framebuffer的bpp为24(RGB888)，则fb_bpp参数配置为24。
framebuffer的bpp可以使用fbset工具来设置，具体使用方法如下：
fbset -fb /dev/fb1 -g 480 320 480 320 32
上面的命令是设置fb1的bpp为32， width为480，height为320。
我们可以通过dpf_480_320.conf里Bgnd widget的update参数调整LCD刷新的间隔，单位为ms。
上述 obtain_frame_from_framebuffer 函数实现从framebuffer里获取RGB raw数据。
由于GD库没有API直接实现把RGB raw数据生成gdImage的功能，我这里写了两个函数 createImageFromRgb32 和 createImageFromRgb24 来实现。
经过上述对lcd4linux源码的改动，我们已经可以输出framebuffer图像到AX206 LCD了。
标签：widget,Image,LCD,bpp,fb,lcd4linux,framebuffer,property,image From： https://www.cnblogs.com/wanglouxiaozi/p/18102315