X-Git-Url: https://git.ao2.it/libam7xxx.git/blobdiff_plain/4612a1475669091669d76054f341cd4a02b5c2d0..7b5a3f952c23daed53a37422db0972950071fc55:/src/am7xxx.c?ds=inline

diff --git a/src/am7xxx.c b/src/am7xxx.c
index f04b638..1035e23 100644
--- a/src/am7xxx.c
+++ b/src/am7xxx.c
@@ -22,6 +22,7 @@
 #include <stdarg.h>
 #include <errno.h>
 #include <libusb.h>
+#include <math.h>
 
 #include "am7xxx.h"
 #include "serialize.h"
@@ -69,7 +70,7 @@ static struct am7xxx_usb_device_descriptor supported_devices[] = {
 };
 
 /* The header size on the wire is known to be always 24 bytes, regardless of
- * the memory configuration enforced by different architechtures or compilers
+ * the memory configuration enforced by different architectures or compilers
  * for struct am7xxx_header
  */
 #define AM7XXX_HEADER_WIRE_SIZE 24
@@ -244,6 +245,7 @@ static void debug_dump_header(am7xxx_context *ctx, struct am7xxx_header *h)
 	(void)ctx;
 	(void)h;
 }
+
 static void trace_dump_buffer(am7xxx_context *ctx, const char *message,
 			      uint8_t *buffer, unsigned int len)
 {
@@ -690,6 +692,68 @@ int am7xxx_get_device_info(am7xxx_device *dev,
 	return 0;
 }
 
+int am7xxx_calc_scaled_image_dimensions(am7xxx_device *dev,
+					unsigned int upscale,
+					unsigned int original_width,
+					unsigned int original_height,
+					unsigned int *scaled_width,
+					unsigned int *scaled_height)
+{
+
+	am7xxx_device_info device_info;
+	float width_ratio;
+	float height_ratio;
+	int ret;
+
+	ret = am7xxx_get_device_info(dev, &device_info);
+	if (ret < 0) {
+		error(dev->ctx, "cannot get device info\n");
+		return ret;
+	}
+
+	/*
+	 * Check if we need to rescale; if the input image fits the native
+	 * dimensions there is no need to, unless we want to upscale.
+	 */
+	if (!upscale &&
+	    original_width <= device_info.native_width &&
+	    original_height <= device_info.native_height ) {
+		debug(dev->ctx, "CASE 0, no rescaling, the original image fits already\n");
+		*scaled_width = original_width;
+		*scaled_height = original_height;
+		return 0;
+	}
+
+	/* Input dimensions relative to the device native dimensions */
+	width_ratio =  (float)original_width / device_info.native_width;
+	height_ratio = (float)original_height / device_info.native_height;
+
+	if (width_ratio > height_ratio) {
+		/*
+		 * The input is proportionally "wider" than the device viewport
+		 * so its height needs to be adjusted
+		 */
+		debug(dev->ctx, "CASE 1, original image wider, adjust the scaled height\n");
+		*scaled_width = device_info.native_width;
+		*scaled_height = (unsigned int)lroundf(original_height / width_ratio);
+	} else if (width_ratio < height_ratio) {
+		/*
+		 * The input is proportionally "taller" than the device viewport
+		 * so its width needs to be adjusted
+		 */
+		debug(dev->ctx, "CASE 2 original image taller, adjust the scaled width\n");
+		*scaled_width = (unsigned int)lroundf(original_width / height_ratio);
+		*scaled_height = device_info.native_height;
+	} else {
+		debug(dev->ctx, "CASE 3, just rescale, same aspect ratio already\n");
+		*scaled_width = device_info.native_width;
+		*scaled_height = device_info.native_height;
+	}
+	debug(dev->ctx, "scaled dimensions: %dx%d\n", *scaled_width, *scaled_height);
+
+	return 0;
+}
+
 int am7xxx_send_image(am7xxx_device *dev,
 		      am7xxx_image_format format,
 		      unsigned int width,