static void jni_get (void *data_in, void *data_out)
{
struct jni_params *in_params = (struct jni_params*)data_in;
struct jni_out_params_char *out_args = (struct jni_out_params_char*)data_out;
char obj_method_name[128];
char obj_method_signature[128];
jclass class_ptr = NULL;
jobject obj = NULL;
jmethodID giid = NULL;
jstring ret_char;
snprintf(obj_method_name, sizeof(obj_method_name), "getStringExtra");
snprintf(obj_method_signature, sizeof(obj_method_signature), "(Ljava/lang/String;)Ljava/lang/String;");
GET_OBJECT_CLASS(in_params->env, class_ptr, in_params->class_obj);
GET_METHOD_ID(in_params->env, giid, class_ptr, in_params->method_name, in_params->method_signature);
CALL_OBJ_METHOD(in_params->env, obj, in_params->class_obj, giid);
GET_OBJECT_CLASS(in_params->env, class_ptr, obj);
GET_METHOD_ID(in_params->env, giid, class_ptr, obj_method_name, obj_method_signature);
CALL_OBJ_METHOD_PARAM(in_params->env, ret_char, obj, giid, (*in_params->env)->NewStringUTF(in_params->env, out_args->in));
if (giid != NULL && ret_char)
{
const char *test_argv = (*in_params->env)->GetStringUTFChars(in_params->env, ret_char, 0);
strncpy(out_args->out, test_argv, out_args->out_sizeof);
(*in_params->env)->ReleaseStringUTFChars(in_params->env, ret_char, test_argv);
}
}
static bool android_gfx_ctx_get_metrics(void *data,
enum display_metric_types type, float *value)
{
jclass metrics_class;
jobject metrics;
jmethodID getMetrics;
struct android_app *android_app = (struct android_app*)g_android;
JNIEnv *env = (JNIEnv*)jni_thread_getenv();
GET_METHOD_ID(env, getMetrics, android_app->activity, "getMetrics", "()Landroid/util/DisplayMetrics;");
if (!getMetrics)
goto error;
CALL_OBJ_STATIC_METHOD(env, metrics, android_app->activity, getMetrics);
GET_OBJECT_CLASS(env, metrics_class, metrics);
/* Density */
float density = (*env)->GetFloatField(env, metrics, (*env)->GetFieldID(env, metrics_class, "density", "F"));
float scaled_density = (*env)->GetFloatField(env, metrics, (*env)->GetFieldID(env, metrics_class, "scaledDensity", "F"));
int density_dpi = (*env)->GetIntField(env, metrics, (*env)->GetFieldID(env, metrics_class, "densityDpi", "I"));
/* Size */
int width_pixels = (*env)->GetIntField(env, metrics, (*env)->GetFieldID(env, metrics_class, "widthPixels", "I"));
int height_pixels = (*env)->GetIntField(env, metrics, (*env)->GetFieldID(env, metrics_class, "heightPixels", "I"));
/* DPI */
/* Apparently xdpi and ydpi can't be trusted to be implemented correctly, so don't try to rely on it...
*
* https://groups.google.com/forum/#!topic/android-developers/QjUlaRohRPI
*
* "The xdpi and ydpi are supposed to be the real DPI of the screen... though as you've seen,
* many devices don't set it correctly. :( This is our fault, it isn't actually used anywhere
* in the platform, so people don't realize they have a bad value, and we haven't had a CTS
* test to try to make sure it is sane (it's not clear how that test should work). Worse, we
* shipping the original Droid with a graphics driver that reports the wrong value here...
* in fact that reported that same damnable 96."
*
* Unfortunately, I don't have a good solution if you want to get the real exactly screen dots per inch.
* One thing you could do is compare xdpi/ydpi with densityDpi and if they are significantly
* far apart, assume the values are bad and just fall back on densityDpi as an approximation.
*
* Be careful on this, because a correctly working device may have densityDpi fairly different
* than the real dpi -- for example the Samsung TAB uses high density even though its screen's
* really density is a fair amount lower than 240."
*/
float xdpi = (*env)->GetFloatField(env, metrics, (*env)->GetFieldID(env, metrics_class, "xdpi", "F"));
float ydpi = (*env)->GetFloatField(env, metrics, (*env)->GetFieldID(env, metrics_class, "ydpi", "F"));
(void)width_pixels;
(void)height_pixels;
(void)scaled_density;
(void)density;
(void)density_dpi;
switch (type)
{
case DISPLAY_METRIC_MM_WIDTH:
/* can't guarantee this to be accurate - so return false anyway. */
*value = xdpi;
return false;
case DISPLAY_METRIC_MM_HEIGHT:
/* can't guarantee this to be accurate - so return false anyway. */
*value = ydpi;
return false;
case DISPLAY_METRIC_DPI:
/* just go with quantized DPI. */
*value = density_dpi;
break;
case DISPLAY_METRIC_NONE:
default:
*value = 0;
return false;
}
return true;
error:
return false;
}