“Call me Hagrid,” he said, “everyone does. An’ like I told
yeh, I’m Keeper of Keys at Hogwarts — yeh’ll know all about Hogwarts,
“Er — no,” said Harry.
Hagrid looked shocked.
Harry said quickly.
“Sorr?” barked Hagrid,
turning to stare at the Dursleys, who shrank back into the shadows.
“It’s them as should be sorry! I knew yeh weren’t gettin’ yer letters
but I never thought yeh wouldn’t even know abou’ Hogwarts, fer cryin’
out loud! Did yeh never wonder where yet parents learned it all?”
“All what?” asked Harry.
“ALL WHAT?” Hagrid thundered. “Now wait jus’ one second!”
He had leapt to his feet. In his anger he seemed to
fill the whole hut. The Dursleys were cowering against the wall.
“Do you mean ter tell me,” he growled at the
Dursleys, “that this boy – this boy! — knows nothin’ abou’ — about
(Harry Potter and the Sorcerer’s Stone)
What does the phrase mean? (I don’t find any relationship between angering and he filling the hut.)
This isn’t so much a question of language as of the reality which language presents. In this case, the sentence refers to both the Dursleys’ perception of Hagrid’s behavior and the behavior itself.
Hagrid is large to begin with; when he leaps to his feet and becomes more threatening he looks larger, because he becomes the focus of the Dursleys and occupies most of their narrowed field of vision.
By the same token, when Hagrid becomes angry he attempts to impose his anger on the Dursleys by becoming not only louder (he thundered) but “larger”: he leaps to his feet, and he probably raises his shoulders and arms and rolls to the balls of his feet in order to appear more threatening. Animals do the same thing: just think of a cornered cat, which hyperextends its legs, arches its back and erects its fur in order to appear larger and therefore more dangerous.
Source : Link , Question Author : Listenever , Answer Author : StoneyB on hiatus